Does each text IO or Display object need to maintain a color stack?

[timholy]

The positive responses to #9349 encouraged me to look into one obvious bug: once it prints something in red, it goes back to :normal rather than :bold printing. It seems to me that fixing this properly means that each relevant display object should maintain state as a stack, and with_output_color should push! and pop! from the stack.

However, I really don't know much about our Display infrastructure or terminals & display in general, so I'm soliciting advice/involvement from experts like @stevengj and @StefanKarpinski.

[vtjnash]

yes.

see #14052 for discussion

[KristofferC]

I think it is unlikely for more advanced color printing to get into Base. To note, Crayons.jl does support exactly this kind of stack: https://github.com/KristofferC/Crayons.jl#advanced-nesting-of-colors-and-styles so in the spirit of moving things out of Base, pointing to that package seems good enough for now. If we need it for our own error reporting it could be brought in later in some sort of standard library style.