~/.xmonad: spawn the editor with meta-e

.xmonad/xmonad.hs

     } `additionalKeys` ([
        ((mod4Mask, xK_b), spawnHere "firefox"),
        ((mod4Mask .|. shiftMask, xK_b), spawnHere "firefox -private-window"),
        ((mod4Mask, xK_e), spawnHere "emacs"),
        ((0, xF86XK_AudioMute), spawn "amixer set Master toggle"),
        ((0, xF86XK_AudioLowerVolume), spawn "amixer set Master 5%-"),