Merge a bunch of documentation fixes from trunk.

Specifically: r1483964, r1483965, r1483968, r1483972, r1483975, r1483977,
r1483984, r1484006, r1484016, r1484017, r1484023, r1485018



git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x@1490367 13f79535-47bb-0310-9956-ffa450edef68