Hello,
Sorry about the [[ ]] not being documented : the only reason is that we want to be 100% sure about the syntax before officially release it and fix it forever.
Speaking about link, you can specify two things:
-
The text to display instead of the full link. Use a space in that case : [[http://www.google.com google]]
-
A tooltip which is displayed when the cursor is over the link: Use {} for that : [[http://www.google.com{This is a tooltip}]]
You will find other examples here
Hope it helps