Add Bus::dispatchSync() doc block (#36888)

Author: axlon

src/Illuminate/Support/Facades/Bus.php

@@ -16,6 +16,7 @@
  * @method static bool|mixed getCommandHandler($command)
  * @method static mixed dispatch($command)
  * @method static mixed dispatchNow($command, $handler = null)
+ * @method static mixed dispatchSync($command, $handler = null)
  * @method static void assertDispatched(string|\Closure $command, callable|int $callback = null)
  * @method static void assertDispatchedTimes(string $command, int $times = 1)
  * @method static void assertNotDispatched(string|\Closure $command, callable|int $callback = null)