attrib.get should have same overload signature as _element.get (GH-97)

Author: PokkaKiyo

lxml-stubs/etree.pyi

@@ -322,7 +322,10 @@ class _Attrib:
     def __getitem__(self, key: _AnyStr) -> _AnyStr: ...
     def __bool__(self) -> bool: ...
     def __len__(self) -> int: ...
-    def get(self, key: _AnyStr, default: _AnyStr = ...) -> Optional[_AnyStr]: ...
+    @overload
+    def get(self, key: _TagName) -> Optional[str]: ...
+    @overload
+    def get(self, key: _TagName, default: _T) -> Union[str, _T]: ...
     def keys(self) -> _ListAnyStr: ...
     def __iter__(self) -> Iterator[_AnyStr]: ...  # actually _AttribIterator
     def iterkeys(self) -> Iterator[_AnyStr]: ...