Detect merge from just the commit message?

When we receive a merge request, the commits are squashed in webstorm and then pushed on the master branch like that.

(not allowed to use any automatic merge tools like the auto merge in gitlab merge requests)

The issue with this of course is that gitlab doesn’t detect that a MR has been merged. I was wondering if there is some commit message syntax I can use that will allow gitlab to detect the merge. Something like, “Merge branch ‘xxx’ into Master”.