util: fix is_picklable() docstring
util: fix is_picklable() docstring

Closes #71

Reported-by: Muhammad Tauqir Ahmad <a3953bccaaf9346b072e6ba2ddb9e7ab9e048454@gmail.com>
Signed-off-by: David Aguilar <9de348c050f7cd1ca590883733c4e531ce610bf4@gmail.com>

dongguangming/jsonpickle,dongguangming/jsonpickle,mandx/jsonpickle,dongguangming/jsonpickle,mandx/jsonpickle,mandx/jsonpickle,dongguangming/jsonpickle,mandx/jsonpickle