- The parser of `git grep`'s output uses `bufio.Scanner`, which is a good
choice overall, however it does have a limit that's usually not noticed,
it will not read more than `64 * 1024` bytes at once which can be hit in
practical scenarios.
- Use `bufio.Reader` instead which doesn't have this limitation, but is
a bit harder to work with as it's a more lower level primitive.
- Adds unit test.
- Resolves https://codeberg.org/forgejo/forgejo/issues/3149
By using git's ability, end users (especially small instance users) do
not need to enable the indexer, they could also benefit from the code
searching feature.
Fix#29996
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Co-authored-by: silverwind <me@silverwind.io>
