Fix candidate cleanup redraw issue if Enter key pressed in Complete Mode.

The completion candidates were not being cleaned up properly if the Enter
key was pressed while in complete mode. This could lead to both candidates
and any program output being mixed on the screen. Cleanly exit complete mode
and redraw when the Enter is pressed while in complete mode.

operation.go

@@ -270,6 +270,10 @@ func (o *Operation) ioloop() {
 			if o.IsSearchMode() {
 				o.ExitSearchMode(false)
 			}
+			if o.IsInCompleteMode() {
+				o.ExitCompleteMode(true)
+				o.buf.Refresh(nil)
+			}
 			o.buf.MoveToLineEnd()
 			var data []rune
 			if !o.GetConfig().UniqueEditLine {