c++: api.location.type

This feature was introduced in 95a2de5695
(which is part of 2.5), but not documented.  Give it a proper name, and
make it public.

* data/c++.m4, data/lalr1.cc, data/glr.cc, data/java.m4: Use
api.location.type instead of location_type.
* src/muscle-tab.c (muscle_percent_variable_update): Map the latter to
the former.
* tests/local.at: Adjust.
* tests/calc.at: Use api.location.type.
Leave tests/java.at with location_type, at least for the time being,
to cover both names.
* doc/bison.texi: Document api.location.type.
(User Defined Location Type): New.
* NEWS: Update.

src/muscle-tab.c

@@ -410,6 +410,7 @@ muscle_percent_variable_update (char const *variable)
   const conversion_type conversion[] =
     {
       { "api.push_pull", "api.push-pull", },
+      { "location_type", "api.location.type", },
       { "lr.keep_unreachable_states", "lr.keep-unreachable-states", },
     };
   char const *res = variable;