add to diagnostic list

Hi,

First all: thanks for this plugin! It does make the whole compile-edit-compile cycle pretty pleasant.

Not even sure if that is possible, but I would like to make it work with https://nvim-mini.org/mini.nvim/doc/mini-extra.html#miniextra.pickers.diagnostic i.e. importing into then `diagnostic` list instead of then `quickfix` one.

Typically, for Rust projects: Neovim is setup with "check on save" on that populates the `diagnostic` list automatically, and I also have `bacon` running in a `:terminal`, but that means in have two warnings/errors lists with potentially different entries.