Fix trim method

src/MbstringExtended.php

@@ -16,7 +16,7 @@ final class MbstringExtended {
      */
     public static function trim (string $string, string $charactersPattern = '\\s'): string {
         /** @noinspection RegExpUnnecessaryNonCapturingGroup */
-        return preg_replace('#(?:^' . $charactersPattern . ')|(?:' . $charactersPattern . '$)#u', '', $string);
+        return preg_replace('#^(?:' . $charactersPattern . ')+|(?:' . $charactersPattern . ')+$#u', '', $string);
     }
     /**
      * Multi-bytes implementation for {@see https://www.php.net/manual/function.ucfirst.php ucfirst}