Doing just `clang` causes `clangd` to be unable to find C headers like
`stdio.h`

I forgot to add a C compiler

I likely won't be adding build systems here since there are a lot of
different build systems that can be used with C

erlang-ls has been archived and they suggest using erlang-language-platform

This only gets created when running `nix fmt`, there isn't anything
here that needs to be locked