[l10n] Check in en-XL.json

We use this debug locale file in e2e tests now, meaning the bots need
this generated file to run tests. Check it in, similar to en-US.json.

Update the presubmit warning to also include en-XL.json.

Presubmit already runs collect-strings.js which generates this file,
which is no longer git-ignored. We will now get presubmit errors if
changes are not checked in, just like with en-US.json.

No-Presubmit: true
Bug: 1136655
Change-Id: I6ba790960fe722a0b453f6687345b41e5e97e8b6
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2673825
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Reviewed-by: Tim van der Lippe <tvanderlippe@chromium.org>
diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index 171ba09..c28158d 100644
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -403,7 +403,7 @@
     results.extend(_checkWithNodeScript(input_api, output_api, script_path))
     results.append(
         output_api.PresubmitNotifyResult(
-            'Please commit en-US.json if changes are generated.'))
+            'Please commit en-US.json/en-XL.json if changes are generated.'))
     return results