Is the parser undergoing refactoring?

The suggested change is more of conversation starter. I could track the introduction of the message to a50b8f1 which is from Nov 2019.

Is the refactor still undergoing? Is there a tracking issue for it?

If not, the N.B. can just be deleted... but maybe the document would need to be updated with the changes from the refactor if that's the case?

Author: smanilov

src/macro-expansion.md

@@ -2,7 +2,7 @@
 
 <!-- toc -->
 
-> N.B. [`rustc_ast`], [`rustc_expand`], and [`rustc_builtin_macros`] are all
+> N.B. as of Nov 2019 [`rustc_ast`], [`rustc_expand`], and [`rustc_builtin_macros`] are all
 > undergoing refactoring, so some of the links in this chapter may be broken.
 
 Rust has a very powerful macro system. In the previous chapter, we saw how