Inline modules

From [this discord conversation.](https://discord.com/channels/695580069837406228/695580069837406231/1300919273270673518)

I have a bunch of related tasks:

```
db-generate-migration
db-migrate
db-nuke
db-reset
db-seed
db-up
db-destroy
```

What I'd like to do is have a more clear separator (like rake):

```
db:generate-migration
db:migrate
```

This is possible with modules, but I cannot create multiple modules in a single Justfile (creating separate Justfiles would be messy in my case).

Two ideas I can think of to solve this problem:

1. Would it be possible to support `:`, `.` in the name grammar?
2. Could we define multiple modules within a single Justfile?

No file, test, or entry point is named in the issue. Start by locating the Justfile name grammar and existing module handling, then determine whether colon and dot names or multiple modules best fit; done means the listed database commands can use the proposed grouped names in one Justfile.

Written by the indexing model from the issue text.