At commit [5666e6b9](5666e6b9fb),
broot refactored the content of the file `/resources/default-conf.hjson`
into multiple files under the directory `/resources/default-conf`, using
[`imports`](5666e6b9fb/resources/default-conf/conf.hjson (L152-L165))
to refer to other configurations.
This refactoring is effective since version 1.14.0 of broot.
After this refactoring, in `xdg.configFile.broot` (which defaults to
`~/.config/broot`):
- we need to copy all potentially referenced files (all files under
`resources/default-conf`),
- except we need to leave out `conf.hjson` which conflicts with the
`conf.toml` generated by home-manager (because broot [accepts both conf.toml and conf.hjson](https://dystroy.org/broot/conf_file/))
To implement this, we use `symlinkJoin` to create the content of
`xdg.configFile.broot` by merging multiple sources.