Real-time editing of issue and merge request title
# Collaboration around this capability is being consolidate on https://gitlab.com/gitlab-org/gitlab/-/issues/21473
### Dependencies
* This should be considered after these are implemented: https://gitlab.com/gitlab-org/gitlab-ce/issues/25051 + https://gitlab.com/gitlab-org/gitlab-ce/issues/25049
### Description
Like google docs, real time collaboration & autosave. Can maybe be done with
- [ShareJS](http://sharejs.org/)
- [Canvas](https://github.com/usecanvas)
- [Hackmd](https://hackmd.io/)
### Scope
- Consider titles only, so that we don't have to worry about more complicated formatting.
- Consider descriptions separately: https://gitlab.com/gitlab-org/gitlab-ce/issues/44162.
issue