Update Rust crate regex to 1.9.4

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
regex	dependencies	patch	1.9.3 -> 1.9.4

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Release Notes

rust-lang/regex (regex)

### [`v1.9.4`](https://togithub.com/rust-lang/regex/blob/HEAD/CHANGELOG.md#194-2023-08-26) [Compare Source](https://togithub.com/rust-lang/regex/compare/1.9.3...1.9.4) \================== This is a patch release that fixes a bug where `RegexSet::is_match(..)` could incorrectly return false (even when `RegexSet::matches(..).matched_any()` returns true). Bug fixes: - [BUG #​1070](https://togithub.com/rust-lang/regex/issues/1070): Fix a bug where a prefilter was incorrectly configured for a `RegexSet`.

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