I don’t think you can add modifier keys in shortcuts.
And this behavior should come out of the box, not me changing stuff around so I can make it usable. For something that I use all the time, sure, but I only use a terminal text editor with git, and I don’t use git that often. For everything else, I use a GUI text editor (mousepad, leafpad, whatever).
It doesn’t have to be X, just the fact that it uses modifier keys is enough. It could be Q or anything else, just please, for the love of god, we live in the 21st century now, all keyboards have modifier keys, please, add modifier keys shortcuts as well.