Make useless Pylint suppressions fail lint

Author: adamtheturtle

pyproject.toml

@@ -244,6 +244,10 @@ MASTER.per-file-ignores = [
     "docs/source/doccmd_*.py:invalid-name",
     "doccmd_README_rst_*.py:invalid-name",
 ]
+# Return non-zero exit code if useless-suppression is emitted.
+MAIN.fail-on = [
+    "useless-suppression",
+]
 DEPRECATED_BUILTINS.bad-functions = [
     # Use Pylint until Ruff can ban bare builtin calls, or until custom rules
     # make this removable: