[css] add ':focus-within' pseudo class #41248
Description
CSS autocomplete does not know 'focus-within' css property. It's currently in use with all modern browsers excluding Edge as listed on caniuse
My setup:
Version 1.19.1
Commit 0759f77bb8d86658bc935a10a64f6182c5a1eeba
Date 2017-12-19T09:41:01.414Z
Shell 1.7.9
Renderer 58.0.3029.110
Node 7.9.0
Architecture x64
Steps to Reproduce:
Create Any CSS element and start typing 'focus-within'.