Tags: patch

There is a new LSP capability allowing the server and client to agree on
a way to count character offsets.  What do you think fo the attached
patch?

It expresses Eglot's preferences as counting character offsets, then
byte offsets, then the UTF-16 nonsense, in that order.

I would also suggest preparing the stage to eventually make
`eglot-current-column-function' and `eglot-move-to-column-function'
obsolete.  For that, I suggest renaming

- eglot-current-column -> eglot--current-column-utf-32
- eglot-lsp-abiding-column -> eglot--current-columns-utf-16
- eglot-move-to-column -> eglot--move-to-columns-utf-32
- eglot-move-to-lsp-abiding-column -> eglot--move-to-columns-utf-16

and then making the old names obsolete aliases of the new names.

(I have tested the utf-32 case superficially, and not at all the utf-8.
So this is a RFC.)