- Stop producing 'backtick' trivia for escaping identifier token. '`'s
are now parts of the token text
- Adjust and simplify C++ libSyntax APIs
- Add 'is_deprecated' property to Trivia.py to attribute SwiftSyntax
APIs
rdar://problem/54810608
Also includes for its substructure:
- function-call-argument
- function-call-argument-list
- symbolic-reference-expression (for the call target)
https://bugs.swift.org/browse/SR-4044