Most regular expression engines don't accept the `{,n}` syntax, but
some other do it (namely Python's `re` library). This introduces a new
parser configuration option that enables the `{,n}` syntax.

PR #1086

PR #1179

PR #1182

This reworks `Utf8Sequences` logic in order to avoid allocating a
0-sized vector and immediately reallocating it for the initial element.
Directly create the populated vector instead.

I was looking at the memory usage patterns of [rolldown] through
heaptrack, and this spot showed up as a potentially-spurious temporary
allocation. The consumer side is [here][consumer side]. I do not have a
specific benchmark for this.

[rolldown]: https://github.com/rolldown/rolldown
[consumer side]: https://github.com/rolldown/rolldown/blob/ce36a195ed4e9ce7c446557cefff4750a2268e01/crates/rolldown/src/utils/extract_hash_pattern.rs#L12

This also likely avoids a spurious alloc or two, although
it assuredly doesn't matter in practice.

I'm not sure why I wrote it like this originally?

PR #1198

PR #1203

We had previously release regex 1.10.4 but omitted a changelog entry for
it. So this adds it.