refactor: Use ast.unparse instead of our own unparser

Now that we build everything using our expressions, and that the unparser is only used in log messages, it's not really useful to keep it in the code base, and we can use `ast.unparse` instead, even if it has some quirks (like using redundant parenthesis wrapping).

pyproject.toml

@@ -31,6 +31,7 @@ classifiers = [
  "Typing :: Typed",
 ]
 dependencies = [
+ "astunparse>=1.6; python_version < '3.9'",
  "colorama>=0.4",
 ]