Correct Handbook content and sidebar heading hierarchy

packages/documentation/copy/en/declaration-files/Publishing.md

@@ -95,7 +95,7 @@ If your type definitions depend on another package:
 
 When TypeScript opens a `package.json` file to figure out which files it needs to read, it first looks at a field called `typesVersions`.
 
-#### Folder redirects (using `*`)
+### Folder redirects (using `*`)
 
 A `package.json` with a `typesVersions` field might look like this:
 
@@ -121,7 +121,7 @@ If we import from `package-name/foo`, we'll try to look for `[...]/node_modules/
 What if we're not running in TypeScript 3.1 in this example?
 Well, if none of the fields in `typesVersions` get matched, TypeScript falls back to the `types` field, so here TypeScript 3.0 and earlier will be redirected to `[...]/node_modules/package-name/index.d.ts`.
 
-#### File redirects
+### File redirects
 
 When you want to only change the resolution for a single file at a time, you can tell TypeScript the file to resolve differently by passing in the exact filenames:
 

packages/documentation/copy/en/handbook-v2/Everyday Types.md

@@ -704,7 +704,7 @@ Enums are a feature added to JavaScript by TypeScript which allows for describin
 It's worth mentioning the rest of the primitives in JavaScript which are represented in the type system.
 Though we will not go into depth here.
 
-#### `bigint`
+### `bigint`
 
 From ES2020 onwards, there is a primitive in JavaScript used for very large integers, `BigInt`:
 
@@ -720,7 +720,7 @@ const anotherHundred: bigint = 100n;
 
 You can learn more about BigInt in [the TypeScript 3.2 release notes](/docs/handbook/release-notes/typescript-3-2.html#bigint).
 
-#### `symbol`
+### `symbol`
 
 There is a primitive in JavaScript used to create a globally unique reference via the function `Symbol()`:
 

packages/documentation/copy/en/handbook-v2/Modules.md

@@ -201,7 +201,7 @@ type Animals = Cat | Dog;
 
 TypeScript has extended the `import` syntax with two concepts for declaring an import of a type:
 
-###### `import type`
+##### `import type`
 
 Which is an import statement which can _only_ import types:
 
@@ -221,7 +221,7 @@ import type { createCatName } from "./animal.js";
 const name = createCatName();
 ```
 
-###### Inline `type` imports
+##### Inline `type` imports
 
 TypeScript 4.5 also allows for individual imports to be prefixed with `type` to indicate that the imported reference is a type:
 
@@ -258,7 +258,7 @@ You can learn more about this syntax in the [modules reference page](/docs/handb
 
 CommonJS is the format which most modules on npm are delivered in. Even if you are writing using the ES Modules syntax above, having a brief understanding of how CommonJS syntax works will help you debug easier.
 
-#### Exporting
+### Exporting
 
 Identifiers are exported via setting the `exports` property on a global called `module`.
 
@@ -365,7 +365,7 @@ import { valueOfPi } from "./constants.js";
 export const twoPi = valueOfPi * 2;
 ```
 
-#### `ES2020`
+### `ES2020`
 
 ```ts twoslash
 // @showEmit
@@ -376,7 +376,7 @@ import { valueOfPi } from "./constants.js";
 export const twoPi = valueOfPi * 2;
 ```
 
-#### `CommonJS`
+### `CommonJS`
 
 ```ts twoslash
 // @showEmit
@@ -387,7 +387,7 @@ import { valueOfPi } from "./constants.js";
 export const twoPi = valueOfPi * 2;
 ```
 
-#### `UMD`
+### `UMD`
 
 ```ts twoslash
 // @showEmit

packages/documentation/copy/en/handbook-v2/Narrowing.md

@@ -483,7 +483,7 @@ In addition, classes can [use `this is Type`](/docs/handbook/2/classes.html#this
 
 Types can also be narrowed using [Assertion functions](/docs/handbook/release-notes/typescript-3-7.html#assertion-functions).
 
-# Discriminated unions
+## Discriminated unions
 
 Most of the examples we've looked at so far have focused around narrowing single variables with simple types like `string`, `boolean`, and `number`.
 While this is common, most of the time in JavaScript we'll be dealing with slightly more complex structures.
@@ -701,12 +701,12 @@ From there, the type system was able to do the "right" thing and figure out the
 Discriminated unions are useful for more than just talking about circles and squares.
 They're good for representing any sort of messaging scheme in JavaScript, like when sending messages over the network (client/server communication), or encoding mutations in a state management framework.
 
-# The `never` type
+## The `never` type
 
 When narrowing, you can reduce the options of a union to a point where you have removed all possibilities and have nothing left.
 In those cases, TypeScript will use a `never` type to represent a state which shouldn't exist.
 
-# Exhaustiveness checking
+## Exhaustiveness checking
 
 The `never` type is assignable to every type; however, no type is assignable to `never` (except `never` itself). This means you can use narrowing and rely on `never` turning up to do exhaustive checking in a `switch` statement.
 

packages/documentation/copy/en/handbook-v2/Type Manipulation/Conditional Types.md

@@ -106,7 +106,7 @@ let c = createLabel(Math.random() ? "hello" : 42);
 //  ^?
 ```
 
-### Conditional Type Constraints
+## Conditional Type Constraints
 
 Often, the checks in a conditional type will provide us with some new information.
 Just like narrowing with type guards can give us a more specific type, the true branch of a conditional type will further constrain generics by the type we check against.
@@ -172,7 +172,7 @@ type Num = Flatten<number>;
 When `Flatten` is given an array type, it uses an indexed access with `number` to fetch out `string[]`'s element type.
 Otherwise, it just returns the type it was given.
 
-### Inferring Within Conditional Types
+## Inferring Within Conditional Types
 
 We just found ourselves using conditional types to apply constraints and then extract out types.
 This ends up being such a common operation that conditional types make it easier.

packages/documentation/copy/en/handbook-v2/Type Manipulation/Mapped Types.md

@@ -46,7 +46,7 @@ type FeatureOptions = OptionsFlags<Features>;
 //   ^?
 ```
 
-### Mapping Modifiers
+## Mapping Modifiers
 
 There are two additional modifiers which can be applied during mapping: `readonly` and `?` which affect mutability and optionality respectively.
 

packages/documentation/copy/en/handbook-v2/Type Manipulation/Template Literal Types.md

@@ -42,7 +42,7 @@ type LocaleMessageIDs = `${Lang}_${AllLocaleIDs}`;
 
 We generally recommend that people use ahead-of-time generation for large string unions, but this is useful in smaller cases.
 
-### String Unions in Types
+## String Unions in Types
 
 The power in template literals comes when defining a new string based on information inside a type.
 
@@ -124,7 +124,7 @@ person.on("firstName", () => {});
 person.on("frstNameChanged", () => {});
 ```
 
-### Inference with Template Literals
+## Inference with Template Literals
 
 Notice that we did not benefit from all the information provided in the original passed object. Given change of a `firstName` (i.e. a `firstNameChanged` event),  we should expect that the callback will receive an argument of type `string`. Similarly, the callback for a change to `age` should receive a `number` argument. We're naively using `any` to type the `callback`'s argument. Again, template literal types make it possible to ensure an attribute's data type will be the same type as that attribute's callback's first argument.
 
@@ -181,7 +181,7 @@ To help with string manipulation, TypeScript includes a set of types which can b
 
 Converts each character in the string to the uppercase version.
 
-##### Example
+#### Example
 
 ```ts twoslash
 type Greeting = "Hello, world"
@@ -197,7 +197,7 @@ type MainID = ASCIICacheKey<"my_app">
 
 Converts each character in the string to the lowercase equivalent.
 
-##### Example
+#### Example
 
 ```ts twoslash
 type Greeting = "Hello, world"
@@ -213,7 +213,7 @@ type MainID = ASCIICacheKey<"MY_APP">
 
 Converts the first character in the string to an uppercase equivalent.
 
-##### Example
+#### Example
 
 ```ts twoslash
 type LowercaseGreeting = "hello, world";
@@ -225,7 +225,7 @@ type Greeting = Capitalize<LowercaseGreeting>;
 
 Converts the first character in the string to a lowercase equivalent.
 
-##### Example
+#### Example
 
 ```ts twoslash
 type UppercaseGreeting = "HELLO WORLD";

packages/documentation/copy/en/javascript/JSDoc Reference.md

@@ -13,7 +13,7 @@ Note:
 - Any tags which are not explicitly listed below (such as `@async`) are not yet supported.
 - Only documentation tags are supported in TypeScript files. The rest of the tags are only supported in JavaScript files.
 
-#### Types
+## Types
 
 - [`@type`](#type)
 - [`@import`](#import)
@@ -25,7 +25,7 @@ Note:
 - [`@satisfies`](#satisfies)
 
 
-#### Classes
+## Classes
 
 - [Property Modifiers](#property-modifiers) `@public`, `@private`, `@protected`, `@readonly`
 - [`@override`](#override)
@@ -34,15 +34,15 @@ Note:
 - [`@class`](#constructor) (or [`@constructor`](#constructor))
 - [`@this`](#this)
 
-#### Documentation
+## Documentation
 
 Documentation tags work in both TypeScript and JavaScript.
 
 - [`@deprecated`](#deprecated)
 - [`@see`](#see)
 - [`@link`](#link)
 
-#### Other
+## Other
 
 - [`@enum`](#enum)
 - [`@author`](#author)

packages/documentation/copy/en/reference/Mixins.md

@@ -213,7 +213,7 @@ This pattern relies less on the compiler, and more on your codebase to ensure bo
 The mixin pattern is supported natively inside the TypeScript compiler by code flow analysis.
 There are a few cases where you can hit the edges of the native support.
 
-#### Decorators and Mixins [`#4881`](https://github.com/microsoft/TypeScript/issues/4881)
+### Decorators and Mixins [`#4881`](https://github.com/microsoft/TypeScript/issues/4881)
 
 You cannot use decorators to provide mixins via code flow analysis:
 
@@ -245,7 +245,7 @@ const playerTwo = (new Player() as unknown) as FreezablePlayer;
 playerTwo.shouldFreeze;
 ```
 
-#### Static Property Mixins [`#17829`](https://github.com/microsoft/TypeScript/issues/17829)
+### Static Property Mixins [`#17829`](https://github.com/microsoft/TypeScript/issues/17829)
 
 More of a gotcha than a constraint.
 The class expression pattern creates singletons, so they can't be mapped at the type system to support different variable types.

packages/documentation/copy/en/reference/Namespaces.md

@@ -125,7 +125,7 @@ Even though the files are separate, they can each contribute to the same namespa
 Because there are dependencies between files, we'll add reference tags to tell the compiler about the relationships between the files.
 Our test code is otherwise unchanged.
 
-##### Validation.ts
+### Validation.ts
 
 ```ts
 namespace Validation {
@@ -135,7 +135,7 @@ namespace Validation {
 }
 ```
 
-##### LettersOnlyValidator.ts
+### LettersOnlyValidator.ts
 
 ```ts
 /// <reference path="Validation.ts" />
@@ -149,7 +149,7 @@ namespace Validation {
 }
 ```
 
-##### ZipCodeValidator.ts
+### ZipCodeValidator.ts
 
 ```ts
 /// <reference path="Validation.ts" />
@@ -163,7 +163,7 @@ namespace Validation {
 }
 ```
 
-##### Test.ts
+### Test.ts
 
 ```ts
 /// <reference path="Validation.ts" />
@@ -208,7 +208,7 @@ tsc --outFile sample.js Validation.ts LettersOnlyValidator.ts ZipCodeValidator.t
 Alternatively, we can use per-file compilation (the default) to emit one JavaScript file for each input file.
 If multiple JS files get produced, we'll need to use `<script>` tags on our webpage to load each emitted file in the appropriate order, for example:
 
-##### MyTestPage.html (excerpt)
+### MyTestPage.html (excerpt)
 
 ```html
 <script src="Validation.js" type="text/javascript" />
@@ -256,7 +256,7 @@ Because this library is loaded through a `<script>` tag (instead of a module loa
 For the TypeScript compiler to see this shape, we use an ambient namespace declaration.
 For example, we could begin writing it as follows:
 
-##### D3.d.ts (simplified excerpt)
+### D3.d.ts (simplified excerpt)
 
 ```ts
 declare namespace D3 {

packages/documentation/copy/en/reference/Triple-Slash Directives.md

@@ -93,7 +93,7 @@ This can lead to problems when other tools are used to process the resulting mod
 
 The `amd-module` directive allows passing an optional module name to the compiler:
 
-##### amdModule.ts
+### amdModule.ts
 
 ```ts
 /// <amd-module name="NamedModule"/>
@@ -102,7 +102,7 @@ export class C {}
 
 Will result in assigning the name `NamedModule` to the module as part of calling the AMD `define`:
 
-##### amdModule.js
+### amdModule.js
 
 ```js
 define("NamedModule", ["require", "exports"], function (require, exports) {