ltlsynt: fix usage for --dot's argument

* bin/ltlsynt.cc (dispatch_print_hoa): Pass the right argument to
print_dot.
* tests/core/ltlsynt.test: Test it.
* NEWS: Mention the bug.

NEWS

@@ -10,6 +10,8 @@ New in spot 2.12.0.dev (not yet released)
     confused by games with "parity min" acceptance using transition
     with several colors (a rather uncommon situation).
 
+  - "ltlsynt ... --print-game --dot=ARGS" was ignoring ARGS.
+
 New in spot 2.12  (2024-05-16)
 
   Build:

bin/ltlsynt.cc

@@ -322,7 +322,7 @@ namespace
       rs->patch_game(game);
 
     if (opt_dot)
-      spot::print_dot(std::cout, game, opt_print_hoa_args);
+      spot::print_dot(std::cout, game, opt_dot_arg);
     else if (opt_print_pg)
       spot::print_pg(std::cout, game);
     else

tests/core/ltlsynt.test

@@ -1085,7 +1085,11 @@ diff outx exp
 
 # Test --dot and --hide-status
 ltlsynt -f 'i <-> Fo' --ins=i --aiger --dot | grep arrowhead=dot
-ltlsynt -f 'i <-> Fo' --ins=i --print-game-hoa --dot | grep 'shape="diamond"'
+ltlsynt -f 'i <-> Fo' --ins=i --print-game-hoa --dot > out
+grep 'shape="diamond"' out
+grep 'Inf(0)' out
+ltlsynt -f 'i <-> Fo' --ins=i --print-game-hoa --dot=bar > out
+grep 'label=<Inf(<font' out
 ltlsynt -f 'i <-> Fo' --ins=i --dot --hide-status > res
 cat >exp <<EOF
 digraph "" {