Fast: Allow color recipes to accept string color values

[nicholasrice]

Currently, color recipes accept either a DesignSystem or a function that accepts a design-system and returns a color. Somtimes, we see this used in a fassion similar to the following:

neutralForegroundRest(() => "#FFF")

Instead of passing a function that returns a string literal, we should just accept a string literal as a paramater type - when the argument is a string, treat the string as a color string, similar to the way we treat the return value of a function argument.

[timb15]

I would like to work on this as my first contribution if possible.

[chrisdholt]

@timb15 sure - feel free to send a PR!

[vitokhangnguyen]

Hi,
Is this one still active? It's been a while so I am wondering if I can give it a try.

[nicholasrice]

@vitokhangnguyen yep - still active!

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.