#3944 speed up type inference by up to 30% percent.

#3867 add CI checks for stray `eprintln`s.

#3842 , #3906 , #3920 copy libprocmacro from rustc. We will be using this library to load proc macro dynamic libraries.

#3863 use .rast extension for serialized syntax trees in tests. This adds syntax highlighting!

#3876 rename complete_scope to hopefully less confusing complete_unqualified_path .

#3882 centralize the logic for computing missing struct fields.

#3826 when doing syntax highlighting, produce a flat list of ranges.

#3909 generate token accessors.

#3913 remove allocation from the "least common ancestor" algorithm.

#3915 format generated code in a more readable way.

#3917 improve tt::Subtree debug print.

#3748 implement Chalk’s debug methods using TLS.

#3926 align tokens names with syn somewhat.

#3940 use actions-rs for cargo audit .

#3942 more precise typing of TypeScript config.

#3949 cleanup cfg handling.