Improve text editing experience to support Shift+DEL to cut text.

It drives me CRAZY that, in your text editor fields, you support Ctrl+V and Shift+Ins(ert) to paste text, support Ctrl+C to copy, and Ctrl+V to paste, but do NOT support Shift+DEL to CUT.

What makes it worse is, the text IS REMOVED from the edit field, but is NOT placed in the cut buffer, and then auto-save kicks in! So to get the text back, you have to use undo, then remember to cut it via the supported mechanism.

I use Shift+DEL ALL THE TIME, it's just a muscle memory issue, and this issue catches me out EVERY time I work in Aha.