The ideal IMO would be to implement this as a macro— so much as the wiki today displays the manifest.yml information generated from doc jobs, the wiki of tomorrow could have a macro which sucks in a similarly-extracted file.
This allows the flexibility to mix and match wiki-editable content where that is appropriate with blobs of source-controlled content, where that is more appropriate. It also offers a sane migration strategy.
The really, really ideal would be if the "mytutorial1.roswiki" file in my repo could actually optionally be itself a templated affair, perhaps supporting a format like mytutorial1.rowiki.em, so that things like blobs of example source code or whatever could be sucked in from marked-off sections of actual working examples which can then be tested during the source build.