Merge branch 'for-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup updates from Tejun Heo:
 "Nothing too interesting. Documentation updates and trivial changes;
  however, this pull request does containt he previusly discussed
  dropping of __must_check from strscpy()"

* 'for-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  Documentation: Fix 'file_mapped' -> 'mapped_file'
  string: drop __must_check from strscpy() and restore strscpy() usages in cgroup
  cgroup, docs: document the root cgroup behavior of cpu and io controllers
  cgroup-v2.txt: fix typos
  cgroup: Update documentation reference
  Documentation/cgroup-v1: fix outdated programming details
  cgroup, docs: document cgroup v2 device controller