Ignore false positive from PHPStan

Author: westonruter

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

@@ -1121,7 +1121,7 @@ private function get_highest_fetchpriority_with_dependents( string $handle, arra
 				}
 			}
 		}
-		$stored_results[ $handle ] = $priorities[ $highest_priority_index ];
+		$stored_results[ $handle ] = $priorities[ $highest_priority_index ]; // @phpstan-ignore parameterByRef.type (We know the index is valid and that this will be a string.)
 		return $priorities[ $highest_priority_index ];
 	}