Coding Standards: Rename the $oSelf variable in WP_MatchesMapRegex::apply().

This resolves a WPCS warning:
{{{
Variable "$oSelf" is not in valid snake_case format, try "$o_self"
}}}

Follow-up to [11853], [38376].

See #59650.

git-svn-id: https://develop.svn.wordpress.org/trunk@57538 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-matchesmapregex.php

@@ -63,8 +63,8 @@ class WP_MatchesMapRegex {
 	 * @return string
 	 */
 	public static function apply( $subject, $matches ) {
-		$oSelf = new WP_MatchesMapRegex( $subject, $matches );
-		return $oSelf->output;
+		$result = new WP_MatchesMapRegex( $subject, $matches );
+		return $result->output;
 	}
 
 	/**