Fix collection of know keys for test, plan and story T001 linter

The original code did not handle fields with dashes
(`restart-max-count`) and internal fields (`serial-number`).

tmt/base.py

@@ -66,6 +66,7 @@
  WorkdirArgumentType,
  cached_property,
  container_field,
+ container_fields,
  dict_to_yaml,
  field,
  git_clone,
@@ -897,7 +898,19 @@ def _export(
 
  def _lint_keys(self, additional_keys: list[str]) -> list[str]:
  """ Return list of invalid keys used, empty when all good """
- known_keys = additional_keys + self._keys()
+
+ known_keys: list[str] = []
+
+ for field_ in container_fields(self):
+ _, key, _, _, metadata = container_field(self, field_.name)
+
+ if metadata.internal:
+ continue
+
+ known_keys.append(key)
+
+ known_keys.extend(additional_keys)
+
  return [key for key in self.node.get() if key not in known_keys]
 
  def lint_validate(self) -> LinterReturn: