ERA001: Ignore script-comments with multiple end-tags

[MichaReiser]

Summary

A script-comment according to PEP 723 starts with # /// script and spans all lines up to # ///.
However, the ´# /// isn't considered the end-tag if the next line is a valid content line according to PEP 723 (# or #<space>).

This PR fixes the handling of script-comments with multipe end-tags.

Fixes #13278

Discussion

This PR changes the rule's semantics to not skip over invalid script comments. Any code in invaid-script comments will get flagged.

I'm torn if that's the right behavior. Arguably, detecting invalid-script-comments should be its own rule. However,
the spec is very cleary about unclosed blocks:

Unclosed blocks MUST be ignored.

Test Plan

Added and update tests

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.

[charliermarsh]

We also have an implementation for this in uv. You could consider copying that over, but this is also fine. Thanks!