Description

As an elementary Nix user unfamiliar with the Nix language, it took me a lot time to discover the lib.mkMerge function and understand its usage for achieving the same effect as specifying both initExtraFirst and initExtra in previous versions.

I hope that including example configurations directly in the documentation would help users like myself (basic Nix users) by saving a lot time when updating configurations to align with upstream changes.

Checklist

• [ x] Change is backwards compatible.

• [x ] Code formatted with nix fmt or ./format.

• [ x] Code tested through nix-shell --pure tests -A run.all
  or nix build --reference-lock-file flake.lock ./tests#test-all using Flakes.

• [ x] Test cases updated/added. See example.

• [x ] Commit messages are formatted like

  {component}: {description}
  
  {long description}