* src/conflicts.c (conflicts_output): Don't output rules never

* src/conflicts.c (conflicts_output): Don't output rules never
reduced here, since anyway that computation doesn't work.
* src/gram.h, src/gram.h (rule_filter_t, rule_useful_p)
(rule_useless_p, rule_never_reduced_p): New.
(grammar_rules_partial_print): Use a filter instead of a range.
Display the title only if needed.
(grammar_rules_print): Adjust.
(grammar_rules_never_reduced_report): New.
* src/tables.c (action_row): Move the computation of rules never
reduced to...
(token_actions): here.
* src/main.c (main): Make the parser before making the report, so
that rules never reduced are computed.
Call grammar_rules_never_reduced_report.
* src/print.c (print_results): Report rules never reduced.
* tests/conflicts.at, tests/reduce.at: Adjust.