@laurent.orseau the key binding c:x;m does it. Does that help?

As for the racket langserver, it is using the same library that drracket uses (and racket mode uses) so you could use that approach but that requires you to expand the program again.

That works but I usually enable “Enable keybinding in menus (overrides Emacs keybindings)”, which prevents it from working

Isn’t there a way to get hold of the keymap that has c:x;m and call the callback programmatically?

Yes, there should be. It may make sense to add a new keybinding to avoid colliding on the platforms that use control as the menu shortcut, tho. (Adding it directly to DrRacket, I mean.)