Fix cursor problem in LetterPrompt

Fixes #300

cmd/micro/view.go

@@ -172,6 +172,8 @@ func (v *View) ScrollDown(n int) {
 func (v *View) CanClose(msg string, responses ...rune) bool {
 	if v.Buf.IsModified {
 		char, canceled := messenger.LetterPrompt("You have unsaved changes. "+msg, responses...)
+		messenger.Clear()
+		messenger.Reset()
 		if !canceled {
 			if char == 'y' {
 				return true