[tex-k] plain.mft: "nodisplay" -> "nodisplays"

[胡亚捷 (Hu Yajie)]

plain.mft misspells plain METAFONT's "nodisplays" as "nodisplay".
It's also very incomplete. Here's what I think is missing:

                       The token ...    should be formatted like ...
====================================    ============================
                                 bye    end
                        rotatedabout    rotatedaround
                                 div    mod
                define_good_x_pixels    define_pixels
                define_good_y_pixels        "
define_whole_vertical_blacker_pixels        "
  define_horizontal_corrected_pixels        "
                     cutdraw, cutoff    filldraw
       pensquare, penrazor, penspeck    pencircle
      proofrule, makelabel, makegrid    screenrule
                            mode_def    mode_setup
                           penlabels    labels
                           gfcorners    screenchars

And the tokens "range" and "thru" can be either in bold or roman font,
but certainly not in italic.