configparser: remove unnecessary defaults from overloads (#15641)

These overloads differ from the other overloads only in the presence
of the `fallback` parameter. If the parameter is not passed, the other
overload should be taken, so `fallback` should be made required on
these overloads for clarity.

Author: JelleZijlstra

stdlib/configparser.pyi

@@ -289,19 +289,19 @@ class RawConfigParser(_Parser):
     def getint(self, section: _SectionName, option: str, *, raw: bool = False, vars: _Section | None = None) -> int: ...
     @overload
     def getint(
-        self, section: _SectionName, option: str, *, raw: bool = False, vars: _Section | None = None, fallback: _T = ...
+        self, section: _SectionName, option: str, *, raw: bool = False, vars: _Section | None = None, fallback: _T
     ) -> int | _T: ...
     @overload
     def getfloat(self, section: _SectionName, option: str, *, raw: bool = False, vars: _Section | None = None) -> float: ...
     @overload
     def getfloat(
-        self, section: _SectionName, option: str, *, raw: bool = False, vars: _Section | None = None, fallback: _T = ...
+        self, section: _SectionName, option: str, *, raw: bool = False, vars: _Section | None = None, fallback: _T
     ) -> float | _T: ...
     @overload
     def getboolean(self, section: _SectionName, option: str, *, raw: bool = False, vars: _Section | None = None) -> bool: ...
     @overload
     def getboolean(
-        self, section: _SectionName, option: str, *, raw: bool = False, vars: _Section | None = None, fallback: _T = ...
+        self, section: _SectionName, option: str, *, raw: bool = False, vars: _Section | None = None, fallback: _T
     ) -> bool | _T: ...
     def _get_conv(
         self,