Top level drop down menus can't be closed with escape

Description

So basically when clicking the drop down menus on the top we basically have to click that button again to close it or click anywhere else on the app i think like making it close by pressing escape key should be a thing as it is in most apps and its convenient as well like pressing maybe the canvas will convert it to the md format and trigger my ocd

Proposed Changes

Add Escape-key handling to the top-level drop down menus so that pressing Escape closes the currently open menu.

If a submenu is open, pressing Escape should close the entire open menu tree.

The existing mouse-based closing behavior should remain unchanged.

Caveats

No known caveats. The change should only affect the behavior of Escape while an application menu is open.

Do you Wish to Attempt Implementing this Yourself?

Yes

Zettlr Version

Right off the develop branch

Your Platform

• Windows
• macOS
• Linux

Operating System Version

Arch Linux

Additional Information

No response