Correctly identify @todo comments as TODOs.

Summary: Allow `@todo` comments to be linted as TODOs as well as `TODO` comments.

Test Plan: I added a new test case (`todo.lint-test`)

Reviewers: #blessed_reviewers, epriestley

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D8389

src/lint/linter/ArcanistXHPASTLinter.php

@@ -2036,9 +2036,15 @@ final class ArcanistXHPASTLinter extends ArcanistBaseXHPASTLinter {
 
     foreach ($comments as $token) {
       $value = $token->getValue();
+      if ($token->getTypeName() === 'T_DOC_COMMENT') {
+        $regex = '/(TODO|@todo)/';
+      } else {
+        $regex = '/TODO/';
+      }
+
       $matches = null;
       $preg = preg_match_all(
-        '/TODO/',
+        $regex,
         $value,
         $matches,
         PREG_OFFSET_CAPTURE);

src/lint/linter/__tests__/xhpast/todo.lint-test

@@ -0,0 +1,10 @@
+<?php
+
+// TODO: Something goes here.
+
+/**
+ * @todo Something else goes here.
+ */
+~~~~~~~~~~
+disabled:3:4
+disabled:6:4