Provide a clarifying comment

Author: Riimu

src/autoload.php

@@ -2,6 +2,7 @@
 
 namespace Violet\StreamingJsonEncoder;
 
+// Bundled autoloader provided as an optional alternative to composer autoloader
 spl_autoload_register(function ($class) {
     if (strncmp($class, __NAMESPACE__, strlen(__NAMESPACE__)) === 0) {
         $path = __DIR__ . strtr(substr($class, strlen(__NAMESPACE__)), ['\\' => DIRECTORY_SEPARATOR]) . '.php';