Update stdlib/configparser.pyi

Author: Akuli

stdlib/configparser.pyi

@@ -146,7 +146,7 @@ class RawConfigParser(_Parser):
     def get(self, section: str, option: str, *, raw: bool = ..., vars: _Section | None = ...) -> str | None: ...
     @overload
     def get(
-        self, section: str, option: str, *, raw: bool = ..., vars: _Section | None = ..., fallback: _T
+        self, section: str, option: str, *, raw: bool = ..., vars: _Section | None = ..., fallback: _T | None
     ) -> str | _T | None: ...
     @overload
     def items(self, *, raw: bool = ..., vars: _Section | None = ...) -> ItemsView[str, SectionProxy]: ...