removal proposal: emacs25*

[Greg Troxel <gdt%lexort.com@localhost>]

Based on earlier discussions:

  * emacs 28 is the standard approach to emacs from pkgsrc.

  * emacs 20 and 21 are more complicated and I am not addressing them;
    they are separate from the normal "add new versions as released and
    gc old versions" process.

  * I hypothesize that there are likely zero users of emacs 25, or at
    least zero users that intend to run 25 rather than upgrade to one of
    26-29.

  * The maintenance cost (including the CPU time in bulk builds) of old
    emacs is low but not quite zero.

  * There is no particular reason not to propose removing 26, but it
    seems easier to see how 25 goes first.

Therefore I propose to remove emacs25 and emacs25-nox11 unless there are
objections.  If you are wanting to keep using emacs25 from pkgsrc,
please explain why, as there are no currently known reasons to use it.

I will remove emacs25 no earlier than 1200Z on 30 August.