My employer has all PRs merged by a bot once they're approved. The bot takes the PR description and uses that as the commit message. The PR is the unit of change that gets reviewed, not the commit. This makes for a nice linear bisectable history of commits (one per PR) with descriptions, references to issues on our tracker, etc. And no need to worry about force pushing, rebasing, etc, unless you want to do so.

Of course it's got the same end result as doing an interactive rebase & combining all the in-progress commits into a single reviewable unit of change with a good commit message, but it's a bit more automatic.