Fix docs build by guarding Self import behind version check

typing_extensions is only a dependency for Python < 3.11, but the
unconditional import caused ModuleNotFoundError on ReadTheDocs (Python
3.12). Use typing.Self from stdlib on 3.11+ and fall back to
typing_extensions on older versions.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: derek73

nameparser/config/__init__.py

@@ -32,7 +32,10 @@
 from collections.abc import Iterable, Iterator, Mapping, Set
 from typing import Any, TypeVar
 
-from typing_extensions import Self
+if sys.version_info >= (3, 11):
+    from typing import Self
+else:
+    from typing_extensions import Self
 
 from nameparser.util import lc
 from nameparser.config.prefixes import PREFIXES