Pull request merge with "--squash"
There should be an option to squash merge the changes at the end of a pull request. This results in a single commit instead of the individual commits plus a merge commit. This is preferred by some development teams to keep the history clear and simple. When this option is available, the user should be able to freely edit the commit message. The ability to do a squash merge should be a configurable option on the target branch, such that users don't accidentally squash to branches, where we don't want it.