Cleaned up go menus.

Up to three different go menus included in the output of (?):

    Red Example Score (2013) - commands

        commands - all (?)                    score package - fix (fix)
                                              score package - remove (rm)
        directory - list (ls)                 score package - rename (ren)
        directory - list long (ll)
        directory - pwd (pwd)                 session - display variables (sdv)

        edit - current stylesheet (Y)         source code - edit (sce)
                                              source code - location (scl)
        go - back (b)
        go - home (h)
        go - score (s)

        go - build (u)
        go - distribution (d)
        go - makers (k)
        go - materials (m)
        go - segments (g)
        go - setup (p)
        go - stylesheets (y)

        go - next score (>)
        go - previous score (<)

        initializer - read only (inro)
        initializer - remove (inrm)
        initializer - stub (ins)

        instrumentation module - read only (imro)

        LilyPond log - read only (llro)

        metadata module - read only (mdmro)
        metadata module - remove (mdmrm)
        metadata module - rewrite (mdmrw)

        metadatum - add (mda)
        metadatum - get (mdg)
        metadatum - remove (mdrm)

        Python - doctest (pyd)
        Python - invoke (pyi)
        Python - test (pyt)

        repository - add (rad)
        repository - commit (rci)
        repository - revert (rrv)
        repository - status (rst)
        repository - update (rup)

    > q

All go menus feature single-key aliases.