Fix the parameter list of object. _rpow_ (GH-GH-16477)

(cherry picked from commit abc0c4fa9970931849b3da598c5980a5b170661e)

Co-authored-by: HongWeipeng <961365124@qq.com>
diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst
index c530e41..e801ee3 100644
--- a/Doc/reference/datamodel.rst
+++ b/Doc/reference/datamodel.rst
@@ -2331,7 +2331,7 @@
             object.__rfloordiv__(self, other)
             object.__rmod__(self, other)
             object.__rdivmod__(self, other)
-            object.__rpow__(self, other)
+            object.__rpow__(self, other[, modulo])
             object.__rlshift__(self, other)
             object.__rrshift__(self, other)
             object.__rand__(self, other)