doc: Fix ssh_userauth_none() function signature.
doc: Fix ssh_userauth_none() function signature.

Thanks to David Tibbe!

BUG: https://red.libssh.org/issues/151

taikoo/libssh,kedazo/libssh,pouete/libssh,pouete/libssh,sebadoom/libssh,kedazo/libssh,sebadoom/libssh,nviennot/libssh,taikoo/libssh,wangshawn/libssh,wangshawn/libssh,robxu9/libssh,taikoo/libssh,Distrotech/libssh,DouglasHeriot/libssh,kedazo/libssh,mwgoldsmith/libssh,taikoo/libssh,nviennot/libssh,wangshawn/libssh,mwgoldsmith/ssh,kedazo/libssh,pouete/libssh,wangshawn/libssh,Distrotech/libssh,pouete/libssh,robxu9/libssh,DouglasHeriot/libssh,Distrotech/libssh,sebadoom/libssh,elastichosts/libssh,sebadoom/libssh,DouglasHeriot/libssh,mwgoldsmith/ssh,robxu9/libssh,mwgoldsmith/ssh,nviennot/libssh,mwgoldsmith/ssh,robxu9/libssh,mwgoldsmith/libssh,elastichosts/libssh,nviennot/libssh,elastichosts/libssh,mwgoldsmith/libssh,DouglasHeriot/libssh,Distrotech/libssh,mwgoldsmith/libssh