Update src/Str.php

src/Str.php

@@ -623,7 +623,7 @@ public static function cleanWhitespace(string $str, string $charlist = " \t\n\r\
         return trim(preg_replace('/[\t\n\r\s]+/', ' ', $str), $charlist);
     }
 
-/**
+    /**
      * Tests a string as a Regular Expression (regex)
      * @return bool true if valid.
      */