Allow hyperlinks on message line in sequence diagram

[awangatsanjel]

When we draw sequence diagrams for a bigger system, they are linked in some way. In a higher lever view, one message among two participants my present a use case in the scope of target participant. That may lead to another sequence diagram. When we store our diagram online, e.g. in GitHub wiki, it is possible to link them together for easy navigation and better overview of the system in and out.

I am thinking, it should be easy to add this feature. There is a feature of Actor Menu which can add hyperlinks to Participant box. Samiliar syntax can be apply to message line easily.