Rename min-font-size to font-min-size like in CSS Fonts Module Level 4

[wimhendrikx]

https://www.w3.org/TR/css-fonts-4/#font-min-max-size-prop

[madeleineostoja]

Ooh nice. Was going to say wouldn't want to cause a conflict between custom props we use vs. potential future specs, but sounds like they do exactly the same thing.

Happy to accept a PR for this — it'd have to be a breaking change though. Might also be worth adding a preserveProperties or similar option, to not remove font-min-size and font-max-size rules from user CSS after processing, in in case native support ever lands. Would also have to rename the respective line-height and letter-spacing props, and update docs and tests. And probably rename the *-range props to be consistent as well (eg: font-lower-range)