Deduplicate in syntax::parse::token with a macro and remove obsolete special identifiers#10891

bors merged 3 commits intorust-lang:masterrust-lang/rust:masterfrom

chris-morgan:macroize-(or-should-that-be-macroify)-syntax--parse--token-so-that-we-don't-make-mistakes-and-to-reduce-the-maintenance-burdenchris-morgan/rust:macroize-(or-should-that-be-macroify)-syntax--parse--token-so-that-we-don't-make-mistakes-and-to-reduce-the-maintenance-burdenCopy head branch name to clipboard