Fixed docs build failure

Author: TomNicholas

xarray/core/dataset.py

@@ -1381,7 +1381,7 @@ def info(self, buf=None):
         See Also
         --------
         pandas.DataFrame.assign
-        netCDF's ncdump
+        ncdump : netCDF's ncdump command line utility
         """
 
         if buf is None:  # pragma: no cover