Description of the new feature/enhancement

This is in some sense the opposite feature from #5833: I'm requesting an option to not open the Windows menu when alt+space is pressed.

I have until now been working with WSL from the Powershell terminal, where the alt+space shortcut to open the Windows menu is disabled. This is convenient since I have alt+space mapped as a shortcut in several WSL applications (such as screen/tmux prefixes), but it no longer works when switching to Terminal.

The usual way of unbinding keys doesn't seem to do anything here:

{ "command": "unbound", "keys": "alt+space" }

It would be nice to have some way of unbinding this in Terminal.