Remove references to obsolete libraries
* doc/emacs/cmdargs.texi (General Variables): * doc/lispintro/emacs-lisp-intro.texi (Lisp History): * doc/lispref/processes.texi (Network): * doc/misc/gnus-coding.texi (Gnus Coding Style): * doc/misc/gnus.texi (Oort Gnus): * doc/misc/smtpmail.texi (Encryption): Remove references to obsolete libraries. (Bug#37964)