Rollup merge of #77640 - ethanboxx:int_error_matching_attempt_2, r=KodrAus

Refactor IntErrorKind to avoid "underflow" terminology

This PR is a continuation of #76455

# Changes

- `Overflow` renamed to `PosOverflow` and `Underflow` renamed to `NegOverflow` after discussion in #76455
- Changed some of the parsing code to return `InvalidDigit` rather than `Empty` for strings "+" and "-". https://users.rust-lang.org/t/misleading-error-in-str-parse-for-int-types/49178
- Carry the problem `char` with the `InvalidDigit` variant.
- Necessary changes were made to the compiler as it depends on `int_error_matching`.
- Redid tests to match on specific errors.

r? ```@KodrAus```

0 files changed, 0 insertions, 0 deletions