added import for MongoClient

Author: elitan

doc/examples/authentication.rst

@@ -12,6 +12,7 @@ If your username or password contains special characters (e.g. '/', ' ',
 or '@') you must ``%xx`` escape them for use in the MongoDB URI. PyMongo
 uses :meth:`~urllib.unquote_plus` to decode them. For example::
 
+ >>> from pymongo import MongoClient
  >>> import urllib
  >>> password = urllib.quote_plus('pass/word')
  >>> password