Add CTRL+Enter to apply password generator changes

[xvallspl]

add the shortcut CTRL+Enter as an option (on top of the current CTRL+S)
to close the Password Generator widget and apply the changes.

Closes #6111

Assuming desired backwards compatibility and keeping the CTRL+S shortcut

Checklist:

• Implement functionality
• Document functionality

Testing strategy

How can I test this? @droidmonkey @phoerious

Type of change

• ✅ New feature (change that adds functionality)
• ✅ Documentation (non-code change)

[phoerious]

I wonder if the QShortcuts should be parented to the button instead of the generator widget. I don't really know how Qt handles accessibility features when there is no direct connection between the button and the shortcut.

[droidmonkey]

Which accessibility would this impact? Keyboard shortcuts are hidden in the UI besides actions in menus, you need to explicitly write about them to expose to end users.

[xvallspl]

For the documentation, I am updating both subsections in the Password Generator section in the User Guide with an extra step, but I am referencing a button that appears in the app but not in the screenshot.

My issue is that I don't have access to a linux box and the screenshots seem to be taken on linux. Can someone help me with this for consistency's sake?

[xvallspl]

I wonder if the QShortcuts should be parented to the button instead of the generator widget. I don't really know how Qt handles accessibility features when there is no direct connection between the button and the shortcut.

FWIW I was not sure I could find a way to connect several shortcuts with the button, so I connected them to the action.

[droidmonkey]

The screenshot in the documentation is the "stand alone" password generator that doesn't have the apply button. For the docs, it would be good enough to just say "When generating a password for an entry, press ...." no need for another screenshot. (we try to limit those cause it bloats the size of the docs)

As for screenshots in documentation, I took those in windows using the light theme. I also run them through https://tinypng.com compression which I found to be the best. I can take any screenshots you want to be extra consistent.

[droidmonkey]

Merging tip: if you merge this yourself now that it's approved, always do a squash merge to get it down to one commit and rebased onto develop. If it's already one commit do a rebase merge. In very rare cases we use a merge commit.

Although looks like I need to fix the macos CI again...

[xvallspl]

Updated the documentation.

@droidmonkey I don't have merging permissions :)