Remove the symmetric helper $bookmark_start since it's not necessary

Author: dmsnell

src/wp-includes/html-api/class-wp-html-tag-processor.php

@@ -1651,7 +1651,6 @@ private function apply_attributes_updates( $shift_this_point = 0 ) {
 		 * replacements adjust offsets in the input document.
 		 */
 		foreach ( $this->bookmarks as $bookmark_name => $bookmark ) {
-			$bookmark_start = $bookmark->start;
 			$bookmark_end   = $bookmark_start + $bookmark->length;
 
 			/*
@@ -1666,18 +1665,18 @@ private function apply_attributes_updates( $shift_this_point = 0 ) {
 			foreach ( $this->lexical_updates as $diff ) {
 				$diff_end = $diff->start + $diff->length;
 
-				if ( $bookmark_start < $diff->start && $bookmark_end < $diff->start ) {
+				if ( $bookmark->start < $diff->start && $bookmark_end < $diff->start ) {
 					break;
 				}
 
-				if ( $bookmark_start >= $diff->start && $bookmark_end < $diff_end ) {
+				if ( $bookmark->start >= $diff->start && $bookmark_end < $diff_end ) {
 					$this->release_bookmark( $bookmark_name );
 					continue 2;
 				}
 
 				$delta = strlen( $diff->text ) - $diff->length;
 
-				if ( $bookmark_start >= $diff->start ) {
+				if ( $bookmark->start >= $diff->start ) {
 					$head_delta += $delta;
 				}