According to the Discourse user trust level documentation, editing all posts requires being a "Leader", the level 4 trust level that is only available as a manual assignment. Someone at level 3, ("Regular"), can recategorize and rename topics, but that's a dynamically assigned level that will take another month-and-a-half or so minimum before people reach it organically.
While I think it's appropriate for StackOverflow, the only real use case that I'd personally be comfortable with here on an ongoing basis would be formatting issues. If that is an ongoing problem, maybe RStudio will decide to recruit a few community members to help out. In the mean time, formatting issues could either be resolved with a reply that does it for them, or a PM advising them on how to fix their post. A PM about a specific post can readily be done from the flag button hidden by the dots menu in each post, which gives you an option to PM the user directly.