Node: Improve documentation (key example)

- Make the key shared – it’s intended to be used in other modules too
- Use ScopedKey – recommended
- Line-wrap – was getting too long
ValueDec: Fix keyword

Copy+paste mistake probably
RedHatTransformer: Fix some missing tokens

- Missing member operator in member metas
- Wrong operator in open bounds (copy+paste mistake)
- Missing commas in tuple type
Reorganize and add token factories

- Add BasicTokenFactory, *very* basic (doesn’t increment token indices,
  stateless)
- Rename TokenFactoryImpl → SimpleTokenFactory
- Add TokenSourceTokenFactory, is also a TokenSource that can be used to
  create a TokenStream

And use TokenSourceTokenFactory in the tests that involve the formatter.
This uncovered a few more missing / wrong token bugs.