Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Per Regents of the University of Calfornia letter, remove advertising
clause.

# If I've done so improperly on a file, please let me know.

mdoc(7) police: sweep.

Document towlower() and towupper() in separate manual pages instead of
trying to confusingly document both on the same page. The new manual pages
are based on tolower(3) and toupper(3) instead of the old towlower(3).