feat: move csharp yasnippet functions to separate file

feat: add snippets for chsarp

Mostly from someone else, but adapted

feat: add yasnippet

feat: add vundo

feat: reintroduce lsp-mode, flycheck

I think moving to eglot, flymake was a mistake.

fix: do not report native comp warnings/errors

They aren't important, especially the warnings are
not important at all for me.

feat: confirm kill when reusing async shell buffer

feat: rename csharp functions with prefix, use built-in functions

feat: no more relative line numbers, long live absolute numbers

feat: add git-link

Also support ditigal.xyz sourcehut hosting

feat: ignore some messages from ghdl syntax reports

feat: add ediff copy both to C

feat: split ediff horizontally

chore: update theme

feat: configure org agenda basics

From Prot's video mostly.

fix: use plain ediff window setup

feat: use lexical binding in init.el

feat: add flymake ghdl backend

fix: show also warnings, fix two outstanding warnings

feat: rebind minibuffer-completion-help

Cannot type ? ...