def warn_for_unused_terminals(compiled_grammar)
      compiled_grammar.terminals.each do |terminal|
        next if terminal.references > 0

        compiled_grammar.add_warning(
          "Unused terminal #{terminal.name.inspect}",
          terminal.source_line
        )
      end
    end
def warn_for_unused_terminals(compiled_grammar)
      compiled_grammar.terminals.each do |terminal|
        next if terminal.references > 0

        compiled_grammar.add_warning(
          "Unused terminal #{terminal.name.inspect}",
          terminal.source_line
        )
      end
    end
Adds warnings for any unused terminals.

 @param [LL::CompiledGrammar] compiled_grammar