Update Note [The flattening story]
I was reading [The flattening story] in GHC.Tc.Solver.Flatten, and noticed that a sentence added by 8dc6d645 had been cut off by e3dbb44f.
I don't know if this was intended, i.e. whether e3dbb44f made it so that other functions than
dischargeFmv can fill in fmvs; if so it would be nice to update this note to say so instead.