add some phpstan array types

src/pocketmine/tile/Banner.php

@@ -166,6 +166,7 @@ class Banner extends Spawnable implements Nameable{
 	 * Returns the data of a pattern with the given ID.
 	 *
 	 * @return mixed[]
+	 * @phpstan-return array{Color?: int, Pattern?: string}
 	 */
 	public function getPatternData(int $patternId) : array{
 		if(!$this->patternExists($patternId)){