add several NamedTuple base classes (#12987)

stdlib/doctest.pyi

@@ -3,7 +3,7 @@ import types
 import unittest
 from _typeshed import ExcInfo
 from collections.abc import Callable
-from typing import Any, ClassVar, NamedTuple
+from typing import Any, NamedTuple, type_check_only
 from typing_extensions import Self, TypeAlias
 
 __all__ = [
@@ -42,17 +42,15 @@ __all__ = [
     "debug",
 ]
 
-# MyPy errors on conditionals within named tuples.
-
 if sys.version_info >= (3, 13):
-    class TestResults(NamedTuple):
-        def __new__(cls, failed: int, attempted: int, *, skipped: int = 0) -> Self: ...  # type: ignore[misc]
-        skipped: int
+    @type_check_only
+    class _TestResultsBase(NamedTuple):
         failed: int
         attempted: int
-        _fields: ClassVar = ("failed", "attempted")  # type: ignore[misc]
-        __match_args__ = ("failed", "attempted")  # type: ignore[misc]
-        __doc__: None  # type: ignore[misc]
+
+    class TestResults(_TestResultsBase):
+        def __new__(cls, failed: int, attempted: int, *, skipped: int = 0) -> Self: ...
+        skipped: int
 
 else:
     class TestResults(NamedTuple):