GNU Emacs Style Key Sequences do not work in master AND shortcut conflicts

Problem Description

Key sequences similar to those used in GNU Emacs , allowing up to four key codes, do not work in the Editor after the changes introduced in PR #7768. I haven’t thought about this case when working on this PR, so this needs to be fix.

@ccordoba12 what do you think is the severity of this?

Also, I’m not sure, but I think there is a problem with how we check for conflicts for these kind of shortcuts in our keyboard preference editor. For example, I do not understand how a shortcut with a keyseq defined as Ctrl+C, then Ctrl+X could work if Ctrl+C is already used for copy and Ctrl+X is already used for cut.

Ressources: https://srinikom.github.io/pyside-docs/PySide/QtGui/QKeySequence.html#gnu-emacs-style-key-sequences https://en.wikipedia.org/wiki/Table_of_keyboard_shortcuts https://www.gnu.org/software/emacs/refcards/pdf/refcard.pdf

[ccordoba12]

Sure, that’s fine.

[jitseniesen]

In Emacs, you do not have to keep the Ctrl key pressed down when typing Ctrl+B, Ctrl+D. However, it is not possible to have both Ctrl+B and Ctrl+B, Ctrl-D shortcuts defined. If you do, the Ctrl-B shortcut takes precedence.