what are these syntaxmap species? I thought pound directives were things like
_ was the placeholder, but those are all apparently keywords.
attribute.id - for syntax highlight treat like
attribute.builtin, in practice I think a known decl attribute in the wrong place or a known type attribute (there are oddities in the syntax map here, check it out for
placeholder is for Xcode placeholder strings from eg. auto completion (and fixits?)
#colorLiteral and friends.
See syntax model header & implementation.