rustfmt: Remove an unnecessary `catch_unwind` use.

The `Input::File` and `Input::Text` cases should be very similar.
However, currently the `Input::File` case uses `catch_unwind` because,
until recently (#125815) there was a fallible version of
`new_parser_from_source_str` but only an infallible version of
`new_parser_from_file`. This difference wasn't fundamental, just an
overlooked gap in the API of `rustc_parse`.

Both of those operations are now fallible, so the `Input::File` and
`Input::Text` cases can made more similar, with no need for
`catch_unwind`. This also lets us simplify an `Option<Vec<Diag>>` to
`Vec<Diag>`.

0 files changed, 0 insertions, 0 deletions