Fix docs

[szabo137]

Closes #14

Checklist

• Tests are passing
• Docs were updated and workflow is passing

[grasph]

I'm not convinced by the new interface name (neither by the package name btw).

However, I prefer to postpone discussions on naming, once we have agreed on the interface definition and on the scope of this package. It's easier to name something, once we know what the thing is. So it's fine for me to keep the new wording for time being.

+1

[Moelf]

I suggest we don't say anything about "object with LV inside" other than pointing out this package just focus on LV and "particle" or whatever shouldn't be <:AbstractLorentzVector. Because they won't (generally) be compatible with LV interface.

[mmikhasenko]

minor comments, can be merged once resolved.
Thanks

[szabo137]

I removed the docs preview todo for now but opened #23

@mmikhasenko if you are happy with my comments, than I would like to merge ;-)