Add CockroachDB error-based fingerprints

[sankalp73]

Fixes #6067.

Adds two passive error-message signatures for CockroachDB under the PostgreSQL block in data/xml/errors.xml: the location-first syntax error (at or near "x": syntax error, distinct from PostgreSQL's verb-first form) and the go.crdb.dev / github.com/cockroachdb hint link. Follows the existing fork-signature pattern.

Validated by feeding sample error pages through htmlParser(): CockroachDB syntax-error and hint pages resolve to PostgreSQL with the CockroachDB fork note, while genuine PostgreSQL/MySQL errors and unrelated prose are unaffected.

[stamparm]

so, basically, you vibe-coded some error-parsing message, to revive the PR that i ignored for ages, most probably without even running any docker tests or anything. man, i'll need to make a NEW FAQ entry - no vibe-coding hobists allowed