Fix typo in chrome/browser/OWNERS

BUG=None

Review-Url: https://codereview.chromium.org/2722603002
Cr-Commit-Position: refs/heads/master@{#453268}

chrome/browser/OWNERS

@@ -28,7 +28,7 @@ per-file chrome_content_browser_client.h=*
 per-file chrome_content_browser_client_browsertest.cc=*
 per-file chrome_content_browser_client_unittest.cc=*
 
-# Mojo manfiests
+# Mojo manifests
 per-file *manifest_overlay.json=set noparent
 per-file *manifest_overlay.json=file://ipc/SECURITY_OWNERS