Akuli and srittau: Remove Python 2 branches from Python 3 stubs (#5461)

* run script and do some manual changes (Akuli)

* do the whole thing manually (srittau)

* merge changes (Akuli)

Co-authored-by: Sebastian Rittau <srittau@rittau.biz>

stdlib/pydoc.pyi

@@ -1,5 +1,5 @@
-import sys
 from _typeshed import SupportsWrite
+from reprlib import Repr
 from types import MethodType, ModuleType, TracebackType
 from typing import (
     IO,
@@ -19,11 +19,6 @@ from typing import (
     Union,
 )
 
-if sys.version_info >= (3,):
-    from reprlib import Repr
-else:
-    from repr import Repr
-
 # the return type of sys.exc_info(), used by ErrorDuringImport.__init__
 _Exc_Info = Tuple[Optional[Type[BaseException]], Optional[BaseException], Optional[TracebackType]]
 
@@ -265,9 +260,3 @@ class ModuleScanner:
 def apropos(key: str) -> None: ...
 def ispath(x: Any) -> bool: ...
 def cli() -> None: ...
-
-if sys.version_info < (3,):
-    def serve(
-        port: int, callback: Optional[Callable[[Any], None]] = ..., completer: Optional[Callable[[], None]] = ...
-    ) -> None: ...
-    def gui() -> None: ...