Rename <!> to <>. Discussed starting at

<http://lists.gnu.org/archive/html/bison-patches/2006-11/msg00039.html>.
* NEWS (2.3a+): Update.
* doc/bison.texinfo (Freeing Discarded Symbols, Bison Symbols):
Update.
* src/parse-gram.y (TYPE_TAG_NONE, generic_symlist_item): Implement.
* src/scan-gram.l (INITIAL): Implement.
* src/symlist.c (symbol_list_default_tagless_new): Update comment.
* src/symlist.h (symbol_list, symbol_list_default_tagless_new): Update
comment.
* tests/actions.at (Default tagless %printer and %destructor,
Default tagged and per-type %printer and %destructor,
Default %printer and %destructor are not for error or $undefined,
Default %printer and %destructor are not for $accept,
Default %printer and %destructor for mid-rule values): Update.
* tests/input.at (Default %printer and %destructor redeclared,
Unused values with default %destructor): Update.

src/parse-gram.c

@@ -699,7 +699,7 @@ static const char *const yytname[] =
   "\"%requires\"", "\"%skeleton\"", "\"%start\"", "\"%token-table\"",
   "\"%verbose\"", "\"%yacc\"", "\"{...}\"", "\"char\"", "\"epilogue\"",
   "\"=\"", "\"identifier\"", "\"identifier:\"", "\"%%\"", "\"|\"",
-  "\"%{...%}\"", "\";\"", "\"type\"", "\"<*>\"", "\"<!>\"", "\"%union\"",
+  "\"%{...%}\"", "\";\"", "\"type\"", "\"<*>\"", "\"<>\"", "\"%union\"",
   "$accept", "input", "prologue_declarations", "prologue_declaration",
   "grammar_declaration", "union_name", "symbol_declaration", "$@1", "$@2",
   "precedence_declaration", "precedence_declarator", "type.opt",