Having to change the package list in two places was a bit redundant. We
can also use `with` patterns now since nixd warns if there are escaping
variables being used.
Note that variables used in multiple places are kept to make it easier
to recognize that those variables must be changed together. Also note
that inherit (pkgs) inside of mkMerge are currently kept to reduce the
diff.
- Removed old hyprlang/hyprlock overlays that are now in nixos-unstable
- Replaced pnpm-shell-completion with the one upstream
- Changed old GPG option to new one
