#13899: \A, \Z, and \B now correctly match the A, Z, and B literals when used inside character classes (e.g. [A]).  Patch by Matthew Barnett.
#13899: merge with 3.2.
Issue #16874 (forward-port from 2.7): fix some documentation formatting.
Issue #16874 (merge from 3.2): fix some documentation formatting.
#16154: fix some doctests in Doc/library.  Patch by Ravi Sinha.
#16154: merge with 3.2.