Yup. Half the comments in this thread are "oh you could do issues in git or something." No, when my PM asks me if bug 123 is fixed, I want a single source of truth. Whether that truth is GitHub, JIRA or something else, it's still a single point of failure.
Maybe the best way would be to put those wiki/issue/whatever-data in the repository itself and just build tools to throw at them. This could be github, gitlab or something local.