RobotsTxt: fix another typo

It's probably high time that I go to bed.

Bug: N/A
Signed-off-by: Yongmin Hong <revi@omglol.email>

PhabExt/PhabricatorCustomRobotsTxtController.php

@@ -42,7 +42,7 @@ public function processRequest() {
     $out[] = 'Disallow: /J*%24*';
     // This is user list.
     // As of 2024-04-17 user list is behind auth but who knows it might change?
-    $out[] = '/people';
+    $out[] = 'Disallow: /people';
     // This is user profile link.
     $out[] = 'Disallow: /p/';
     // Phorge specific entries end here.