Add transpiled JS to job summary if changed

Author: mbg

.github/workflows/script/check-js.sh

@@ -16,6 +16,10 @@ if [ ! -z "$(git status --porcelain)" ]; then
     # If we get a fail here then the PR needs attention
     >&2 echo "Failed: JavaScript files are not up to date. Run 'rm -rf lib && npm run-script build' to update"
     git status
+
+    echo "### Transpiled JS diff" >> $GITHUB_STEP_SUMMARY
+    git diff --output="$RUNNER_TEMP/js.diff"
+    cat "$RUNNER_TEMP/js.diff" >> $GITHUB_STEP_SUMMARY
     exit 1
 fi
 echo "Success: JavaScript files are up to date"