Consider YAML syntax highlighting in metadata comments

[anderseknert]

While they are comments, they're also interpreted as YAML, and all issues around editing YAML — like adding an extra whitespace somewhere, and have that change the semantics of parsing — still apply. I wonder if it would help to have metadata blocks recognized (and highlighted) as YAML. It would help make them stand out from regular comments, but would also mean that VS Code could do YAML-specific checks on them.

I'm not sure about this, as there's also a risk of metadata appearing to be too prominent in policies. But a POC to test this would be helpful for making an informed decision.