class RuboCop::AST::ProcessedSource

now respects using parser for backwards compatibility.
It is also not fully compatible with Ruby 3.4 but for
The Parser gem does not support Ruby 3.5 or later.

def default_parser_engine(ruby_version)
  if ruby_version >= 3.4
    :parser_prism
  else
    :parser_whitequark
  end
end