Feature request: support just module

`just` has module feature:

https://github.com/casey/just?tab=readme-ov-file#modules1190

According to README, justfile can declare modules by `mod` statement like this:

```just
# justfile
mod bar

a:
  @echo A
```

```just
# bar.just
b:
  @echo B
```

Then `@echo B` can be call like this:

```
$ just bar b
B

$ just bar::b
B
```

However, `fzf-make` doesn't detect modules currently.