Ability to prevent child-content from being coloured

Hi @jxnblk, I just added XRay to my project, working great! However, I was hoping I'd be able to colour the grid-lines separately to the child content. I see that in the code, you apply the CSS "color" rule and therefore it changes the colour of all text below it! I attempted to override this rule in the style prop, but the "color" rule is applied afterwards.

As a feature requests, It'd be ideal if this was possible?

Thanks!

PS: I also noticed that the style prop isn't supported in the propTypes, and therefore complains in dev mode. Unsure if this is by design or not!

Start at the XRay component where the CSS color rule is applied and inspect how the style prop and propTypes are handled. Make grid-line coloring independent from child content and resolve the style-prop validation concern; verify that both behaviors work without changing existing layout debugging.

Written by the indexing model from the issue text.