Display items as we display rules.

Display items as we display rules.
* src/gram.h, src/gram.c (rule_lhs_print): New.
* src/gram.c (grammar_rules_partial_print): Use it.
* src/print.c (print_core): Likewise.
* tests/conflicts.at (Defaulted Conflicted Reduction),
(Unresolved SR Conflicts): Adjust.
(Unresolved SR Conflicts): Adjust and rename as...
(Resolved SR Conflicts): this, as was meant.
* tests/regression.at (Web2c Report): Adjust.