Fix attribute arguments highlighting and better support CPP

[wouterj]

@javiereguiluz after seeing my changes online, I discovered 2 minor bugs that are fixed with this PR:

• Highlight public/protected/private when using constructor property promotion
• Fix highlighting attribute arguments (these were now parsed as function definition parameters instead of invocation arguments, e.g. lacking named argument support)

[javiereguiluz]

This is great! Wouter, you keep improving highlighting more and more 🙌 Thanks 🙇