Print error message if bat not found on path

tests/syntax-tests/create_highlighted_versions.py

@@ -64,6 +64,9 @@ def create_highlighted_versions(output_basepath):
                 file=sys.stderr,
             )
             sys.exit(1)
+        except FileNotFoundError:
+            print("Error: Could not execute 'bat'. Please make sure that the executable is available on the PATH.")
+            sys.exit(1)
 
 
 if __name__ == "__main__":