Several API docs fixes

Fixing various API docs issues found by the EnglishBreakfastNetwork's
code checker Krazy.

Submitted by Illya Kovalevskyy <illya.kovalevskyy@gmail.com>, completing
a Google Code-in task.

CCMAIL: illya.kovalevskyy@gmail.com
REVIEW: 107723
DIGEST: Google Code-in contribution