gh-126970: Correct LOAD_GLOBAL stack order documentation

[limadog9]

Describe the current LOAD_GLOBAL stack order in its main documentation: when the low argument bit is set, the global is followed by NULL. Record the stack-order change under Python 3.13 while keeping the flag's introduction under Python 3.11.

Fixes #126970.

Validation:

• Checked the interpreter's LOAD_GLOBAL macro and verified disassembly, the low-bit flag, stack effects, and call/value behavior on a current free-threaded debug build.
• Full HTML documentation build with warnings treated as errors.
• Sphinx lint and patchcheck.

• Issue: inconsistency in 3.13 LOAD_GLOBAL docs #126970

[read-the-docs-community]

Documentation build overview

📚 cpython-previews | 🛠️ Build #35258728 | 📁 Comparing 705535c against main (6044c62)

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1 file changed

± library/dis.html