Remove extra parents param in Commit.__init__ docstring

It was listed earlier and was incorrect, not corresponding to the
position or type of this initializer's actual `parents` parameter.

Author: EliahKagan

git/objects/commit.py

@@ -112,15 +112,12 @@ def __init__(
         encoding: Union[str, None] = None,
         gpgsig: Union[str, None] = None,
     ) -> None:
-        R"""Instantiate a new :class:`Commit`. All keyword arguments taking ``None`` as
+        """Instantiate a new :class:`Commit`. All keyword arguments taking ``None`` as
         default will be implicitly set on first query.
 
         :param binsha:
             20 byte sha1.
 
-        :param parents: tuple(Commit, ...)
-            A tuple of commit ids or actual :class:`Commit`\s.
-
         :param tree:
             A :class:`~git.objects.tree.Tree` object.