This is a tiny change that, perhaps slightly shady, permits us to use
the `annotate-snippets` renderer without its mandatory header (which
wasn't there in `annotate-snippets 0.9`). Specifically, we can now do
this:
Level::None.title("")
The combination of a "none" level and an empty label results in the
`annotate-snippets` header being skipped entirely. (Not even an empty
line is written.)
This is maybe not the right API for upstream `annotate-snippets`, but
it's very easy for us to do and unblocks the upgrade (albeit relying on
a vendored copy).
Ref https://github.com/rust-lang/annotate-snippets-rs/issues/167
This merely adds the crate to our repository. Some cosmetic changes are
made to make it work in our repo and follow our conventions, such as
changing the name to `ruff_annotate_snippets`. We retain the original
license information. We do drop some things, such as benchmarks, but
keep tests and examples.
