Originally this was intended as a [simple Version bump](https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=225059), but [Dima Panov requested](https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=225059#c1) I fix the `DESKTOP` option. This made me have a closer look at the `Makefile` and perform more extensive changes. These are this diff's changes:
- Reorder `Makefile` variables according to [Porter's Handbook Chapter 15](https://www.freebsd.org/doc/en/books/porters-handbook/porting-order.html).
- Add `DESKTOP_IMPLIES` as requested by Dima Panov.
- Unconditionally install completions according to [Porter's Handbook Chapter 6.31.](https://www.freebsd.org/doc/en/books/porters-handbook/shell-completion.html). This adds extra build, but no run dependencies.
- Unconditionally install manual pages and remove the `MANPAGES` option. A program without any documentation is worthless. This adds extra build, but no run dependencies.
- Rename `DOXYGEN` option to `MAN3` (like Perl or OpenSSL) to make its effect more clear. This manual page remains behind an option to avoid pulling in large build dependencies by default.
- Let the ports framework handle the compression of `notmuch-mutt.1`.
- Remove `RUBY` option as it never did anything. There are no build or install instructions in the `Makefile` nor `%%RUBY%%` references in `pkg-plist`. Building with the `RUBY` option enabled makes absolutely no difference to the produced package. The only thing ever requiring the Ruby bindings to the notmuch library is the Vim client. But this one isn't built either.
Do these changes warrant an entry in `UPDATING`?