Improve presubmit check messaging

Also add oneline status on gclient gitmodules.

R=jojwang@google.com

Change-Id: I05c9f856ce6fd1c3ebf1dc7da672d25196a4cb67
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/4771975
Reviewed-by: Joanna Wang <jojwang@chromium.org>
Auto-Submit: Josip Sokcevic <sokcevic@chromium.org>
Commit-Queue: Joanna Wang <jojwang@chromium.org>
Commit-Queue: Josip Sokcevic <sokcevic@chromium.org>
diff --git a/gclient.py b/gclient.py
index ce1a489..5dffe75 100755
--- a/gclient.py
+++ b/gclient.py
@@ -2729,6 +2729,8 @@
       f.write(f'[submodule "{path}"]\n\tpath = {path}\n\turl = {url}\n')
       if 'condition' in dep:
         f.write(f'\tgclient-condition = {dep["condition"]}\n')
+  print('.gitmodules and gitlinks updated. Please check git diff and '
+        'commit changes.')
 
 
 @metrics.collector.collect_metrics('gclient flatten')