Summary
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This updates the regex in `ruff-ecosystem` to catch syntax errors in an
effort to prevent bugs like #16874. This should catch `ParseError`s,
`UnsupportedSyntaxError`s, and the upcoming `SemanticSyntaxError`s.
Test Plan
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I ran the ecosystem check locally comparing v0.11.0 and v0.11.1 and saw
a large number (2757!) of new syntax errors. I also manually tested the
regex on a few lines before that.
If we merge this before #16878, I'd expect to see that number decrease
substantially in that PR too, as another test.