Change merge locally text for rebasing

Description

It is possible to configure a project to do a fast-forward only merge for accepting merge requests. However, if gitlab is unable to execute a rebase by itself, it hints the user with a "merge locally" to do a merge in stead of a rebase. The goal for this feature would be to have the "merge locally" hint match the configured "merge method"

Proposal

Either create fixed "merge locally" help messages for each of the merge methods or create a feature to load the "merge locally" hint from the repository itself.

Links / references

Documentation blurb

The feature should work out of the box.

~"feature proposal"