Syntax highlighting now available for VSCode

[bob2517]

To install the ACSS syntax highlighter for VSCode, go here.

https://github.com/Active-CSS/active-css-vscode-syntax-highlighting

It's not officially finalised, hence why it's a currently a manual install. But it's literally a copy/paste job to get it set up as an extension in VSCode. Once I've had some feedback and it seems ok I'll publish it officially so it can be installed properly.