ruff

11cfe2ea - [red-knot] Enforce specifying paths for mdtest code blocks in a separate preceding line (#15890)

[red-knot] Enforce specifying paths for mdtest code blocks in a separate preceding line (#15890) ## Summary Resolves #15695, rework of #15704. This change modifies the Mdtests framework so that: * Paths must now be specified in a separate preceding line: `````markdown `a.py`: ```py x = 1 ``` ````` If the path of a file conflicts with its `lang`, an error will be thrown. * Configs are no longer accepted. The pattern still take them into account, however, to avoid "Unterminated code block" errors. * Unnamed files are now assigned unique, `lang`-respecting paths automatically. Additionally, all legacy usages have been updated. ## Test Plan Unit tests and Markdown tests. --------- Co-authored-by: Carl Meyer <carl@astral.sh>