A wiki is a terrible instrument for writing software documentation. For example, there is no revision control to track changes as required by by changes in the code, there is much duplication. I could go on, and on, why a wiki is not optimal for any documentation associated to a software project.
Which wiki engine do you have in mind? There certainly is revision control in MediaWiki, Confluence, and others. Granted, I wouldn't use those in place of a source code revision control system such as git. There are generally no "annotate"/"blame" or "pickaxe" features. I would agree with writing something code-friendly in the first place, examples of which would include DocBook and Restructured Text.
Better to use a system like DITA or dockbook.