should has_wiki be true?

[cbeck88]

most of our repos don't have wikis

[jcape]

I can see it going either way, TBH. We aren't actually using it on the repos we do have it turned on for, but the intent was to have, e.g. SGX FFI stuff documented in the SGX FFI repo's wiki.

I'm OK to just say "nope, needs to be in docs.rs instead".