Eliminate capture groups from regexp_replace optimization

Split anchored ^prefix(capture)suffix.*$ patterns into separate prefix
and content regexes (no capture groups). Uses two find() calls instead
of captures() + expand(), avoiding capture-group tracking overhead and
String allocation in the hot loop.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Dandandan

datafusion/functions/src/regex/regexpreplace.rs

@@ -277,10 +277,7 @@ fn try_build_extract_parts(pattern: &str, replacement: &str) -> Option<ExtractPa
 
     // Build content regex: ^(capture inner) — anchored so it matches
     // right where the prefix ended
-    let content_hir = Hir::concat(vec![
-        Hir::look(Look::Start),
-        (*cap.sub).clone(),
-    ]);
+    let content_hir = Hir::concat(vec![Hir::look(Look::Start), (*cap.sub).clone()]);
     let content_re = Regex::new(&content_hir.to_string()).ok()?;
 
     Some(ExtractParts {
@@ -588,9 +585,7 @@ fn _regexp_replace_static_pattern_replace<T: OffsetSizeTrait>(
                                 None
                             }
                         });
-                        vals.append_slice(
-                            extracted.unwrap_or(val).as_bytes(),
-                        );
+                        vals.append_slice(extracted.unwrap_or(val).as_bytes());
                     }
                     new_offsets.append(T::from_usize(vals.len()).unwrap());
                 });