Update facade docblocks

Author: taylorotwell

src/Illuminate/Support/Facades/DB.php

@@ -103,6 +103,7 @@
  * @method static string getTablePrefix()
  * @method static \Illuminate\Database\Connection setTablePrefix(string $prefix)
  * @method static \Illuminate\Database\Grammar withTablePrefix(\Illuminate\Database\Grammar $grammar)
+ * @method static void withoutTablePrefix(\Closure $callback)
  * @method static string getServerVersion()
  * @method static void resolverFor(string $driver, \Closure $callback)
  * @method static \Closure|null getResolver(string $driver)