fix: correct formatting in server.php

Author: xentixar

examples/09-cached-discovery-stdio/server.php

@@ -12,7 +12,7 @@
  * file that was distributed with this source code.
  */
 
-require_once dirname(__DIR__) . '/bootstrap.php';
+require_once dirname(__DIR__).'/bootstrap.php';
 chdir(__DIR__);
 
 use Mcp\Server;