Self in struct is not highlighted as usage

[lnicola]

Originally posted by @0x7CFE in #3887 (comment)

[lnicola]

CC @Veykril

[Veykril]

The issue here is that we basically only do a text search for the identifier HostState here before then resolving those found identifiers, but for this case we would have to do a search for Self as well which. This shouldn't cause many problems but its probably better to do this after I'm done refactoring those areas.