Replace broken type annotations with type comments

Fixes #3635.

src/_pytest/mark/structures.py

@@ -136,9 +136,9 @@ class Mark(object):
     #: name of the mark
     name = attr.ib(type=str)
     #: positional arguments of the mark decorator
-    args = attr.ib(type="List[object]")
+    args = attr.ib()  # type: List[object]
     #: keyword arguments of the mark decorator
-    kwargs = attr.ib(type="Dict[str, object]")
+    kwargs = attr.ib()  # type: Dict[str, object]
 
     def combined_with(self, other):
         """