Remove builtins.ellipsis pseudo-type

This type never existed at runtime, and was replaced by `types.EllipsisType`.

Author: srittau

stdlib/builtins.pyi

@@ -1980,10 +1980,6 @@ def __import__(
 ) -> types.ModuleType: ...
 def __build_class__(func: Callable[[], CellType | Any], name: str, /, *bases: Any, metaclass: Any = ..., **kwds: Any) -> Any: ...
 
-# Backwards compatibility hack for folks who relied on the ellipsis type
-# existing in typeshed in Python 3.9 and earlier.
-ellipsis = EllipsisType
-
 Ellipsis: EllipsisType
 NotImplemented: NotImplementedType