Fix truncated filenames in emacs.tap

The files in the emacs.tap tar have their basenames truncated to 14
bytes. Fix the three affected files:

  ./emacs4.2/maclib/{electric-lisp. => electric-lisp.ml}
  ./emacs4.2/man/{introduction.m => introduction.mss}
  ./emacs4.2/man/{incr-search.ms => incr-search.mss}

This modification invalidates the respective header checksums, so those
are recomputed and replaced, matching the original formatting.