refactor(preg): split PregMatches reads into get() and name()

PregMatches keyed both forms of a capture group through CaptureKey, so
every read built one: a usize wrapped in an enum, or worse, a String
allocated to name a group that regex::Captures can look up from a &str.
It now mirrors regex::Captures instead -- get() takes the group number,
name() the group name -- and the enum drops out of the type entirely.

That is 285 call sites across 59 files, and the named ones carry most of
the win: `matches.get(&CaptureKey::ByName("host".to_string()))` reads as
`matches.name("host")`. ProcessExecutor loses a `user_key` binding that
existed only to build the key once.

CaptureKey stays as the key type of PregMatchesAll and
PregMatchesAllWithOffsets, where numbered and named entries share one
IndexMap and a key type is the point. Five files still name it.

Also retargets the two preg_match_all comments that described the
occurrence count through `matches[&CaptureKey::ByIndex(0)].len()`, an
Index impl these types no longer carry.

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

1 files changed, 2 insertions, 4 deletions

diff --git a/crates/shirabe/src/util/github.rs b/crates/shirabe/src/util/github.rs
index 28a13738..570a33bb 100644
--- a/crates/shirabe/src/util/github.rs
+++ b/crates/shirabe/src/util/github.rs
@@ -8,7 +8,7 @@ use crate::io::io_interface;
 use crate::util::HttpDownloader;
 use crate::util::ProcessExecutor;
 use indexmap::IndexMap;
-use shirabe_pcre::{CaptureKey, Preg};
+use shirabe_pcre::Preg;
 use shirabe_php_shim::Catch as _;
 use shirabe_php_shim::{PhpMixed, date_local, in_array_loose, php_regex, stripos, strtolower};
 
@@ -326,9 +326,7 @@ impl GitHub {
                 continue;
             }
             if let Some(caps) = Preg::match3(php_regex!(r"{\burl=(?P<url>[^\s;]+)}"), header) {
-                return caps
-                    .get(&CaptureKey::ByName("url".to_string()))
-                    .map(str::to_string);
+                return caps.name("url").map(str::to_string);
             }
         }