Reformatted return

Changed the return of the method in line with suggestions from @JoostK.

laravel/html.php

@@ -421,9 +421,7 @@ class HTML {
 	 */
 	protected static function encoding()
 	{
-		if(static::$encoding===null) static::$encoding = Config::get('application.encoding');
-
-		return static::$encoding;
+		return static::$encoding ?: static::$encoding = Config::get('application.encoding');
 	}
 
 	/**