Strengthen the warning against using SerialCookie and SmartCookie.     (If they're security holes, should they be documented at all?) Minor rewrites.
Strengthen the warning against using SerialCookie and SmartCookie.
    (If they're security holes, should they be documented at all?)
Minor rewrites.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator