Added message_comment_width config option

src/config/config.h

@@ -481,6 +481,7 @@ struct inheritable_diagram_options {
         "generate_condition_statements", false};
     option<std::vector<std::string>> participants_order{"participants_order"};
     option<bool> generate_message_comments{"generate_message_comments", false};
+    option<unsigned> message_comment_width{"message_comment_width", 25};
     option<bool> debug_mode{"debug_mode", false};
     option<bool> generate_metadata{"generate_metadata", true};