Allow saving without closing of the note

[Mladia]

Currently, after clicking "save note", the view changes back to the note overview. For a user to continue editing of the same note, clicking "edit" is needed to go back to editing view.

Allowing the option to quick save the currently edited note without changing the view or closing of the note will help usability.

Originally referenced by @dullage in #59 (comment)

[dullage]

Thanks 👍. I'll have a think about this.

[bverkron]

+1 for this!

[jokob-sk]

+1

[dullage]

I've just merged a change into the develop branch that allows for notes to be saved without closing the note:

Additionally, I've added 2 new keyboard shortcuts available when editing a note:

CTRL-Enter - Save (without closing)
Escape - Close the note

If anyone wants to give this a go before release you can pull and run the dullage/flatnotes:develop image.

[dullage]

This change is now available in 5.2.0. 🚀