refactor(pcre): return the Preg $matches instead of filling an out-param

`Composer\Pcre\Preg` fills `$matches` through a by-ref parameter, and the
port mirrored that with a `&mut` (or `Option<&mut>`) out-param plus a
bool or count return. Callers had to declare an empty map one line ahead
of the call, and the type never said the map is only meaningful when the
call matched. Return the matches instead:

- match3/match4/is_match3/is_match4 -> Option<PregMatchedGroups>
- is_match_named -> Option<PregNamedGroups>
- match_all2/is_match_all -> PregMatchesAll
- is_match_all_with_offsets3 -> PregMatchesAllWithOffsets

Nothing is lost: the bool is `Option::is_some()`, and the occurrence
count is the length of any one column of a PREG_PATTERN_ORDER map, now
spelled `PregMatchesAll::occurrence_count()`. is_match() still answers
the bool question directly for callers that want no groups.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

0 files changed, 0 insertions, 0 deletions