release 1.1.1 about reglang

[palmskog]

@chdoc fine by me to make a release based on the current master (and it's also a good opportunity to update stuff in gh-pages, which is not up to date).

Note though that we shouldn't use Dune in the opam archive package (this way of building with Dune will cease to work), so you may want to leave that part to me.

[chdoc]

@palmskog I just tagged the release, can you do the opam package and the doc?