* Support comp.nix.
* Re-order overlays and modules dependency-last for sanity.
* Re-export `xmonad.modernise`.
NIX.md:
* Document comp.nix.
* Simplify example system flake, removing direct dependency on the
xmonad flake.
* Advise sane module ordering.
* Include and document `modernise` workaround.
* Clarify user-substituted `<foo>` values.
.gitignore:
* Include nix 'result' symlink.
There are multiple ways one could use XMonad with nix, so a separate
file for documenting all of this seems appropriate. E.g., when it
contains the respective installation instructions (e.g, "normally" as
instructed in the NixOS wiki, via stack, via flake, ...) we could link
to it from INSTALL.md.
For now it's a good place to document the new `develop.nix`
functionality.
Co-authored-by: Ivan Malison <IvanMalison@gmail.com>
