Enhancement > Notes link/x-ref to md files

Thanks for this package, it's the first Mind Map I've actually got (because I can write the structure in MD rather than futzing around in a UI).

I have a very specific use case: I'm using the package to plot a novel. And one thing I'd find super-useful is to be able to open/cross-reference other .md files from nodes.

So for example, I've got a plot line:
* Something happens
* Character involved
* WIDGET used
In this situation there's two possible x-references:
* Character
* WIDGET

I've attempted this using `[link name](permalink)` but this renders as plain text, not a link.

Thanks again

L.