docs: add missing and new /proc/PID/status file entries, fix typos

docs: add missing and new /proc/PID/status file entries, fix typos

Signed-off-by: Nathan Scott <nathans@redhat.com>
Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>