Split 'color keywords' into named-color and system-color (#17924)
Split 'color keywords' into named-color and system-color (#17924)

* Split 'color keywords' into named-color and system-color

* Alphabetise subfeatures
chrisdavidmills/browser-compat-data,mdn/browser-compat-data,mdn/browser-compat-data,chrisdavidmills/browser-compat-data