Color switch of action button of messages not documanted

[rugk]

When hovering the warning action button e.g. it has yellow-70 and the text is grey-90 as usual.

This is the contrast ration: 5.22.

This is how that looks:

Okay the contrast checker says, with white text, this is only 3.74, so it is worse, but IMHO it is much more readable:

/cc @ENT8R

[rugk]

Oh wait, it is actually already shown in the guide:

But again not documented by text!