Is there any documentation for the wiki markup for a Sharepoint wiki?
Solution 1:
There are some notes at this Stackoverflow question:
Does SharePoint in any way support Wiki markup languages?
There is also this general SharePoint forum on TechNet.
Solution 2:
I'm the program manager responsible for wikis in SharePoint.
Correct - [[ for links is the only syntax SharePoint wikis support in both 2007 and 2010