2016: Creating a MR (Merge Request) requires the name of a project, not of its wiki.
The workaround would then be similar to the one described in your linked answer
- having a dedicated repo "project" being a fork/clone of the wiki
- making your MR to this wiki project/fork
- pushing from this fork back to the original wiki repo
2022: this is followed by Epic 7107, which refers to this workaround:
Accepting merge requests on wikis
It's possible to work around the limitation of Wiki permissions
by creating a mirror of the git wiki backing the wikis.
This way more users can suggest changes to the wiki by submitting merge requests.
It's not as easy as editing the wiki, but at least provides
a way for outside contributors to participate.
To do this, you'll need to create project access tokens in the
Wiki and use the repository mirror feature to replicate the wiki
into a separate project.
In the Wiki project, head for the Settings: Access Tokens page
and create a new token with write_repository access
optionally, create a new project for the wiki, for example called
wiki-replica.
You can also use the same project as the wiki
if you do not plan to host other source code specific to that
project there.
We'll call this the "wiki replica" in either case
In the wiki replica, head for the Settings: Mirroring repositories
section and fill in the details for the wiki HTTPS clone URL:
Git repository URL: the HTTPS URL of the Git repository (which
you can find in the Clone repository page on the top-right
of the wiki)
Important: Make sure you add a username to
the HTTPS URL, otherwise mirroring will fail.
For example, this wiki URL:
https://gitlab.torproject.org/tpo/tpa/team.wiki.git
should actually be:
https://wiki-replica@gitlab.torproject.org/tpo/tpa/team.wiki.git
Mirror direction: push (only "free" option, pull is non-free)
Authentication method: Password (default)
Password: the Access token you created in the first
step
Keep divergent refs: checked (optional, should make sure
sync works in some edge cases)
Mirror only protected branches: checked (to keep merge
requests from being needlessly mirrored to the wiki)
When you click the Mirror repository
button, a sync will be
triggered.
Refresh the page to see status, you should see the Last successful update
column updated.
When you push to the replica, the wiki should be updated.
Naturally, because of limitations of GitLab, you cannot pull changes
from the wiki to the replica.
But considering only a limited set of
users have access to the wiki in the first place, this shouldn't be a
problem as long as everyone pushes to the replica.