In the XML output, list useless and unused symbols and rules with the

In the XML output, list useless and unused symbols and rules with the
useful ones and add a "usefulness" attribute.  Discussed starting at
<http://lists.gnu.org/archive/html/bison-patches/2007-09/msg00017.html>.
* src/gram.c (grammar_rules_partial_print_xml): Remove.
(grammar_rules_print_xml): Print all rules instead of just those
useful in the grammar, and add a "usefulness" attribute.
* src/gram.h (grammar_rules_partial_print_xml): Remove prototype.
* src/print-xml.c (print_rules_useless_in_parser): Remove.
(print_grammar): Print all nonterminals instead of just useful ones,
and add a "usefulness" attribute to nonterminals and terminals.
(print_xml): Don't print a separate "reductions" or
"rules-useless-in-parser" element.
* src/reduce.c (reduce_output): Use reduce_token_unused_in_grammar.
(reduce_xml): Remove.
(reduce_token_unused_in_grammar): New.
(reduce_nonterminal_useless_in_grammar): New.
* src/reduce.h (reduce_xml): Remove prototype.
(reduce_token_unused_in_grammar): Add prototype.
(reduce_nonterminal_useless_in_grammar): Add prototype.
* data/xslt/xml2text.xsl: Update for XML changes.
* data/xslt/xml2xhtml.xsl: Update for XML changes.
* tests/reduce.at (Useless Terminals): Update output.
(Useless Rules): Update output.
(Reduced Automaton): Update output.

Say "Terminals unused in grammar" instead of "Unused terminals".
* NEWS (2.3a+): Update.
* doc/bison.texinfo (Understanding): Update example output.
* src/reduce.c (reduce_output): Implement.
* data/xslt/xml2text.xsl: Implement.
* data/xslt/xml2xhtml.xsl: Implement.