Convention use(plugin()) should be maintained

[vanthome]

All rework plugins are used like
css.use(colors());
but this one is:
css.use(color);
This breaks an undocumented convention and would be nice if it would adhere to it.

[MoOx]

It's not really an "undocumented" convention.
Ex: rework-calc doesn't return a function.
Plugins that return a function are plugins that need (or accept) option(s) or that need a specific scope (for keeping internal stuff in memory).
Like rework-calc, it's not needed to return a function because this plugin only does a simple conversion.

That being said, I plan to add preserve option (like I did for rework-vars) so this plugin can act as a fallback, so you will be probably happy with that :) (-> need for option -> module is a function)

[vanthome]

sure :) thanks for the outlook!