Never explicitly inherit from object in Python 3-only stubs (#6777)

stdlib/unicodedata.pyi

@@ -24,7 +24,7 @@ def name(__chr: str, __default: _T = ...) -> str | _T: ...
 def normalize(__form: str, __unistr: str) -> str: ...
 def numeric(__chr: str, __default: _T = ...) -> float | _T: ...
 
-class UCD(object):
+class UCD:
     # The methods below are constructed from the same array in C
     # (unicodedata_functions) and hence identical to the methods above.
     unidata_version: str