The Haskell Wiki license allows for dumps and subsequent changes (and relicencing if required): HaskellWiki:Copyrights - HaskellWiki.
I am not sure about the license of contributions before 2006-1-14. What happens if a page has contributions from before 2006, do we have to ask the contributors in this case? Many will not beavailable anymore.
A more pragmatic side: How would we call this dump? It is not anymore a Wiki in the sense that it won’t be a MediaWiki. Calling it “book” would be a bit to much of the “Let’s copy what Rust is doing” mentality.
Notes on how to create dumps: