update gh action with tweaks from https://github.com/pantheon-systems…

…/documentation/pull/9180/files

.github/workflows/prettier.yml

@@ -38,7 +38,9 @@ jobs:
             echo "Fixing the following files:"
             echo "$CHANGED_FILES"
             echo "$CHANGED_FILES" | xargs npx prettier --write
-            echo "CHANGED_FILES=$CHANGED_FILES" >> $GITHUB_ENV
+            # Join the filenames into a single line with space separation.
+            JOINED_FILES=$(echo $CHANGED_FILES | tr '\n' ' ')
+            echo "CHANGED_FILES=$JOINED_FILES" >> $GITHUB_ENV
           else
             echo "No files to format"
           fi
@@ -52,7 +54,8 @@ jobs:
             git config user.email "[email protected]"
             git add .
             git commit -m "Apply Prettier formatting"
-            git push
+            git push origin HEAD:${{ github.head_ref }}
+
             DIFF_OUTPUT=$(git diff HEAD~1 HEAD)
             echo "DIFF_OUTPUT<<EOF" >> $GITHUB_ENV
             echo "$DIFF_OUTPUT" >> $GITHUB_ENV
@@ -65,7 +68,8 @@ jobs:
           GH_TOKEN: ${{ github.token }}
         run: |
           if [ -n "${{ env.DIFF_OUTPUT }}" ]; then
-            gh pr comment ${{ github.event.pull_request.number }} --body "$(echo -e "Hi from your friendly robot! 🤖\n\nI've applied Prettier formatting to the following files:\n\n${{ env.CHANGED_FILES }}\n\nThe full diff is below:\n\n<details>\n<summary>Click to expand</summary>\n\n\`\`\`diff\n$DIFF_OUTPUT\n\`\`\`\n</details>")"
+            CURRENT_COMMIT=$(git rev-parse --short HEAD)
+            gh pr comment ${{ github.event.pull_request.number }} --body "$(echo -e "Hi from your friendly robot! 🤖\n\nI've applied Prettier formatting to the following files in $CURRENT_COMMIT:\n\n\`${{ env.CHANGED_FILES }}\`\n\nThe full diff is below. Please review the changes.\n\n<details>\n<summary>Click to expand</summary>\n\n\`\`\`diff\n$DIFF_OUTPUT\n\`\`\`\n</details>")"
           else
             echo "No Prettier changes"
           fi