fix(weakref): make proxy return ProxyType[_T] for non-callable _T

Signed-off-by: Pavel Dydyshka <paul.dydyshko@gmail.com>

Author: pddshk

stdlib/_weakref.pyi

@@ -12,4 +12,4 @@ def getweakrefs(object: Any, /) -> list[Any]: ...
 @overload
 def proxy(object: _C, callback: Callable[[_C], Any] | None = None, /) -> CallableProxyType[_C]: ...
 @overload
-def proxy(object: _T, callback: Callable[[_T], Any] | None = None, /) -> Any: ...
+def proxy(object: _T, callback: Callable[[_T], Any] | None = None, /) -> ProxyType[_T]: ...