fix: concatenate via printf

Author: denchenko

.github/workflows/generate-messageflow-docs.yml

@@ -58,14 +58,13 @@ jobs:
             git config user.email "messageflow-ci-bot@example.com"
             git add -A
 
-            echo "Sync: ${{ github.event.client_payload.source_repo }}@${{ github.event.client_payload.source_sha }}" > /tmp/commit_msg.txt
+            COMMIT_MSG="Sync: ${{ github.event.client_payload.source_repo }}@${{ github.event.client_payload.source_sha }}"
 
             # Add changes details if available
-            echo ${{ steps.generate-docs.outputs.changelog }}
-
             if [ -n "${{ steps.generate-docs.outputs.changelog }}" ]; then
-              echo "" >> /tmp/commit_msg.txt
-              echo "${{ steps.generate_docs.outputs.changes }}" >> /tmp/commit_msg.txt
+              printf "%s\n\n%s\n" "$COMMIT_MSG" "${{ steps.generate-docs.outputs.changelog }}" > /tmp/commit_msg.txt
+            else
+              echo "$COMMIT_MSG" > /tmp/commit_msg.txt
             fi
 
             git commit -F /tmp/commit_msg.txt