Problem: users didn't know to use the nix unstable channel in the HOWTO
Problem: users didn't know to use the nix unstable channel in the HOWTO

Solution: add it to docs

sjmackenzie/fractalide,dmichiels/fractalide,fractalide/fractalide,dmichiels/fractalide,dmichiels/fractalide,fractalide/fractalide,sjmackenzie/fractalide,fractalide/fractalide,sjmackenzie/fractalide