doc: Define a doc group for the callbacks.
doc: Define a doc group for the callbacks.

mwgoldsmith/libssh,wangshawn/libssh,sebadoom/libssh,wangshawn/libssh,pouete/libssh,nviennot/libssh,nviennot/libssh,jahrome/libssh,DouglasHeriot/libssh,taikoo/libssh,rofl0r/libssh,Distrotech/libssh,miloj/libssh-v0.5,jahrome/libssh,Distrotech/libssh,rofl0r/libssh,substack/libssh,sebadoom/libssh,bigcat26/libssh-mod,bigcat26/libssh-mod,jt1/honeypot-libssh,bigcat26/libssh-mod,kedazo/libssh,miloj/libssh-v0.5,taikoo/libssh,mwgoldsmith/ssh,pouete/libssh,substack/libssh,wangshawn/libssh,kedazo/libssh,mwgoldsmith/ssh,rofl0r/libssh,mwgoldsmith/ssh,robxu9/libssh,robxu9/libssh,kedazo/libssh,bigcat26/libssh-mod,DouglasHeriot/libssh,Distrotech/libssh,elastichosts/libssh,sebadoom/libssh,robxu9/libssh,jt1/honeypot-libssh,mwgoldsmith/ssh,jahrome/libssh,mwgoldsmith/libssh,elastichosts/libssh,jt1/honeypot-libssh,rofl0r/libssh,jt1/honeypot-libssh,nviennot/libssh,taikoo/libssh,miloj/libssh-v0.5,substack/libssh,taikoo/libssh,Distrotech/libssh,DouglasHeriot/libssh,kedazo/libssh,DouglasHeriot/libssh,robxu9/libssh,substack/libssh,mwgoldsmith/libssh,miloj/libssh-v0.5,wangshawn/libssh,pouete/libssh,sebadoom/libssh,elastichosts/libssh,jahrome/libssh,nviennot/libssh,mwgoldsmith/libssh,pouete/libssh