Add missing attributes of type (#2544)

All these attributes can be seen when using `dir(type)`.

In the future we should be discussing if certain methods on object (like
__eq__) should really be there. IMO this should be defined on type where it
actually also appears when using `dir`.

stdlib/3/builtins.pyi

@@ -75,12 +75,19 @@ class classmethod:  # Special, only valid as a decorator.
     def __get__(self, obj: _T, type: Optional[Type[_T]] = ...) -> Callable: ...
 
 class type:
-    __bases__ = ...  # type: Tuple[type, ...]
-    __name__ = ...  # type: str
-    __qualname__ = ...  # type: str
-    __module__ = ...  # type: str
-    __dict__ = ...  # type: Dict[str, Any]
-    __mro__ = ...  # type: Tuple[type, ...]
+    __base__: type = ...
+    __bases__: Tuple[type, ...] = ...
+    __basicsize__: int = ...
+    __dict__: Dict[str, Any] = ...
+    __dictoffset__: int = ...
+    __flags__: int = ...
+    __itemsize__: int = ...
+    __module__: str = ...
+    __mro__: Tuple[type, ...] = ...
+    __name__: str = ...
+    __qualname__: str = ...
+    __text_signature__: Optional[str] = ...
+    __weakrefoffset__: int = ...
 
     @overload
     def __init__(self, o: object) -> None: ...
@@ -97,6 +104,8 @@ class type:
     def mro(self) -> List[type]: ...
     def __instancecheck__(self, instance: Any) -> bool: ...
     def __subclasscheck__(self, subclass: type) -> bool: ...
+    @classmethod
+    def __prepare__(metacls, __name: str, __bases: Tuple[type, ...], **kwds: Any) -> Mapping[str, Any]: ...
 
 class super:
     @overload