Update warning msg

Author: makbigc

pandas/core/series.py

@@ -573,7 +573,7 @@ def nonzero(self):
         """
         msg = ("Series.nonzero() is deprecated "
                "and will be removed in a future version."
-               "Use np.nonzero() instead")
+               "Use np.nonzero(Series.values) instead")
         warnings.warn(msg, FutureWarning, stacklevel=2)
         return self._values.nonzero()