feat: implement format strings

src/vm/fzl_vm_debug.c

@@ -20,6 +20,10 @@ void fzl_vm_print_ops(fzl_vm_t *vm)
 
     switch (vm->ops[i])
     {
+      case FZL_OPCODE_BUILD_STR:
+        printf("BUILD_STR %zu\n", vm->ops[++i]);
+        break;
+
       case FZL_OPCODE_DEREFERENCE:
         printf("DEREFERENCE\n");
         break;
@@ -163,9 +167,6 @@ void fzl_vm_print_ops(fzl_vm_t *vm)
       case FZL_OPCODE_JMP:
         printf("JMP IP: %ld\n", vm->ops[++i]);
         break;
-
-      default:
-        printf("<UNKNOWN>\n");
     }
   }
 }