Add key combinations for ctrl-delete and shift-delete (#3284)

Currently there is not option to bind ctrl-delete and shift-delete. As
suggested by issue #3240, shift-delete could be used to bind "delete
entry from history" as it is a common way to do so in other
applications, e.g. browsers.

This, however, does only implement to use the key combination itself and
does not assign a default action to any of them. This does enable to
call one's all predefined actions. With the exec action this can
expanded like the issue #3240 suggested.
If desirable, the key combinations could later get a default behavior.

Co-authored-by: Junegunn Choi <junegunn.c@gmail.com>

src/tui/tcell.go

@@ -413,6 +413,12 @@ func (r *FullscreenRenderer) GetChar() Event {
 		case tcell.KeyHome:
 			return Event{Home, 0, nil}
 		case tcell.KeyDelete:
+			if ctrl {
+				return Event{CtrlDelete, 0, nil}
+			}
+			if shift {
+				return Event{SDelete, 0, nil}
+			}
 			return Event{Del, 0, nil}
 		case tcell.KeyEnd:
 			return Event{End, 0, nil}