Add type parameter to remaining Series.astype overloads.

Author: JanEricNitschke

pandas-stubs/core/series.pyi

@@ -1320,14 +1320,14 @@ class Series(IndexOpsMixin[S1], NDFrame):
         dtype: CategoryDtypeArg,
         copy: _bool = ...,
         errors: IgnoreRaise = ...,
-    ) -> Series: ...
+    ) -> Series[Any]: ...
     @overload
     def astype(
         self,
         dtype: ObjectDtypeArg | VoidDtypeArg | ExtensionDtype | DtypeObj,
         copy: _bool = ...,
         errors: IgnoreRaise = ...,
-    ) -> Series: ...
+    ) -> Series[Any]: ...
     def copy(self, deep: _bool = ...) -> Series[S1]: ...
     def infer_objects(self) -> Series[S1]: ...
     @overload