proc.5: Fixes various references to kernel docs in Documentation/

Especially the change to .rst format in the kernel Documentation/
tree has rendered many of the references in this manual page
obsolete. Fix them.

Reported-by: Vito Caputo <vcaputo@pengaru.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
1 file changed