Support responsive line-height

[perrin4869]

Could be really useful, might send a pull request tomorrow

[madeleineostoja]

There's a discussion going at madeleineostoja/rucksack#31 about this. Not sure if it falls within responsive-font-sizes purview, especially since line-height can already be a unitless value, and it would have to parse line-height values separately. Might be better suited to an accompanying responsive-line-height plugin.

[perrin4869]

Well, this repo is called responsive-type, and line-height is part of type, so I think it belongs here conceptually. Also, a lot of the implementation details are similar, so practically speaking sharing the same codebase will make things cleaner.

I'll work on the pull request in a little bit, maybe also throw in a bit of documentation for the supported unit combinations as well. Thanks!

[madeleineostoja]

Yep that's fair. Definitely open to a pull request.

[perrin4869]

Cool, you can close this now :)