Add @disjoint_base decorator in the stdlib (#14599)

And fix some other new stubtest finds.

stdlib/array.pyi

@@ -3,7 +3,7 @@ from _typeshed import ReadableBuffer, SupportsRead, SupportsWrite
 from collections.abc import Iterable, MutableSequence
 from types import GenericAlias
 from typing import Any, ClassVar, Literal, SupportsIndex, TypeVar, overload
-from typing_extensions import Self, TypeAlias, deprecated
+from typing_extensions import Self, TypeAlias, deprecated, disjoint_base
 
 _IntTypeCode: TypeAlias = Literal["b", "B", "h", "H", "i", "I", "l", "L", "q", "Q"]
 _FloatTypeCode: TypeAlias = Literal["f", "d"]
@@ -17,6 +17,7 @@ _T = TypeVar("_T", int, float, str)
 
 typecodes: str
 
+@disjoint_base
 class array(MutableSequence[_T]):
     @property
     def typecode(self) -> _TypeCode: ...