fix: improve name key match

[gardar]

This refines the matching for the name key to only target instances where it's an item in a list. This change significantly reduces the likelihood of false positives.

Related Issue: #109

The highlighting now looks like this:

However, there are still some edge cases to be aware of:

Which you could work around like so:

[pearofducks]

I haven't merged this yet, I'm taking a bit to think about it.

The regex here also grabs the - which I really don't like - and I'm also hesitant to introduce any regex - YAML is pretty flexible and there's all sorts of bonkers things people could get up to, I'd rather stick to extending what the YAML syntax file provides than start bashing that with custom regex/selections.