Avoid rendering desugared prefix matches in error messages (#14195)
## Summary
When the user provides a requirement like `==2.4.*`, we desugar that to
`>=2.4.dev0,<2.5.dev0`. These bounds then appear in error messages, and
worse, they also trick the error message reporter into thinking that the
user asked for a pre-release.
This PR adds logic to convert to the more-concise `==2.4.*`
representation when possible. We could probably do a similar thing for
the compatible release operator (`~=`).
Closes https://github.com/astral-sh/uv/issues/14177.
Co-authored-by: Zanie Blue <contact@zanie.dev>
