lr.default-reductions: rename "full" value to "most".

lr.default-reductions: rename "full" value to "most".

Unlike "consistent" and "accepting", "full" doesn't answer the
question of "which states".
* doc/bison.texinfo (%define Summary): Update.
(Default Reductions): Update.
* src/print.c (print_reductions): Update.
* src/reader.c (prepare_percent_define_front_end_variables):
Update.
* src/tables.c (action_row): Update.
* tests/input.at (%define enum variables): Update.
* tests/reduce.at (%define lr.default-reductions): Update.