Remove object as the only ancestor for classes in Python 3 stubs.

stdlib/3/_markupbase.pyi

@@ -1,6 +1,6 @@
 from typing import Tuple
 
-class ParserBase(object):
+class ParserBase:
     def __init__(self) -> None: ...
     def error(self, message: str) -> None: ...
     def reset(self) -> None: ...

stdlib/3/builtins.pyi

@@ -80,7 +80,7 @@ class type:
     def __instancecheck__(self, instance: Any) -> bool: ...
     def __subclasscheck__(self, subclass: type) -> bool: ...
 
-class super(object):
+class super:
     @overload
     def __init__(self, t: Any, obj: Any) -> None: ...
     @overload

stdlib/3/calendar.pyi

@@ -19,7 +19,7 @@ def leapdays(y1: int, y2: int) -> int: ...
 def weekday(year: int, month: int, day: int) -> int: ...
 def monthrange(year: int, month: int) -> Tuple[int, int]: ...
 
-class Calendar(object):
+class Calendar:
     def __init__(self, firstweekday: int = 0) -> None: ...
     def getfirstweekday(self) -> int: ...
     def setfirstweekday(self, firstweekday: int) -> None: ...

stdlib/3/difflib.pyi

@@ -47,7 +47,7 @@ def ndiff(a: Sequence[str], b: Sequence[str],
           charjunk: Callable[[str], bool] = ...
           ) -> Iterator[str]: ...
 
-class HtmlDiff(object):
+class HtmlDiff:
     def __init__(self, tabsize: int = ..., wrapcolumn: int = ...,
                  linejunk: Callable[[str], bool] = ...,
                  charjunk: Callable[[str], bool] = ...

stdlib/3/json.pyi

@@ -50,7 +50,7 @@ def load(fp: IO[str],
     object_pairs_hook: Optional[Callable[[List[Tuple[Any, Any]]], Any]] = ...,
     **kwds: Any) -> Any: ...
 
-class JSONEncoder(object):
+class JSONEncoder:
     item_separator = ...  # type: str
     key_separator = ...  # type: str
 
@@ -69,7 +69,7 @@ class JSONEncoder(object):
     def encode(self, o: Any) -> str: ...
     def iterencode(self, o: Any, _one_shot: bool=False) -> Iterator[str]: ...
 
-class JSONDecoder(object):
+class JSONDecoder:
 
     object_hook = None  # type: Callable[[Dict[str, Any]], Any]
     parse_float = ...  # Callable[[str], Any]