I18n: Set description of Crowdin PR using GH Actions (#78424)

* I18n: Set description of Crowdin PR using GH Actions

* pin action sha

* Apply suggestions from code review

Co-authored-by: Alex Khomenko <Clarity-89@users.noreply.github.com>

---------

Co-authored-by: Alex Khomenko <Clarity-89@users.noreply.github.com>

.github/workflows/i18n-crowdin-fix-files.yml

@@ -19,9 +19,10 @@ jobs:
     name: Fix files
     runs-on: ubuntu-latest
 
-    # write permission needed to commit changes back in
+
     permissions:
-      contents: write
+      contents: write # needed to commit changes back into the PR
+      pull-requests: write # needed to update PR description
 
     steps:
       - uses: actions/checkout@v4
@@ -40,7 +41,27 @@ jobs:
         run: yarn i18n:extract
 
       - name: Commit changes
-        uses: stefanzweifel/git-auto-commit-action@v5
+        uses: stefanzweifel/git-auto-commit-action@8756aa072ef5b4a080af5dc8fef36c5d586e521d # v5.0.0
         with:
           commit_message: "Github Action: Auto-fix i18n files"
           file_pattern: public/locales/*/grafana.json
+
+      - name: Update PR description
+        uses: devindford/Append_PR_Comment@32dd2619cd96ac8da9907c416c992fe265233ca8 # v1.1.3
+        if: ${{ ! contains(github.event.pull_request.body, 'Steps for merging') }}
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          body-update-action: prefix
+          body-template: |
+            :robot: Automatic sync of translations from Crowdin.
+
+            Steps for merging:
+              1. Wait for the "Github Action: Auto-fix i18n files" commit that may be required for CI to pass.
+              2. A quick sanity check of the changes and approve. Things to look out for:
+                - No changes to the English strings. The source of truth is already in the main branch, NOT Crowdin.
+                - Translations maybe be removed if the English phrase was removed, but there should not be many of these
+                - Anything else that looks 'funky'. Ask if you're not sure.
+              3. Approve & (Auto-)merge. :tada:
+
+            If there's a conflict, close the pull request and **delete the branch**. Crowdin will recreate the pull request eventually.
+            Remember, the longer this pull request is open, the more likely it is that it'll get conflicts.