verbatim: do not report "Invalid code" when the terminal is resized

During verbatim input at most four integers are produced (the longest
possible unicode sequence), so use the value 999 to indicate a special
condition (a screen resize) that should not enter anything into the
buffer AND should not produce any error message or beep.

This fixes https://savannah.gnu.org/bugs/?58923.

Bug existed since version 5.0, commit 5899181a.

src/prompt.c

@@ -200,9 +200,9 @@ void do_statusbar_verbatim_input(void)
 
 	bytes = get_verbatim_kbinput(bottomwin, &count);
 
-	if (count > 0)
+	if (0 < count && count < 999)
 		inject_into_answer(bytes, count);
-	else
+	else if (count == 0)
 		beep();
 
 	free(bytes);

src/text.c

@@ -3016,15 +3016,17 @@ void do_verbatim_input(void)
 
 	/* When something valid was obtained, unsuppress cursor-position display,
 	 * insert the bytes into the edit buffer, and blank the status bar. */
-	if (count > 0) {
+	if (0 < count && count < 999) {
 		if (ISSET(CONSTANT_SHOW))
 			lastmessage = VACUUM;
 
 		inject(bytes, count);
 		wipe_statusbar();
-	} else
+	} else if (count == 0)
 		/* TRANSLATORS: An invalid verbatim Unicode code was typed. */
 		statusline(ALERT, _("Invalid code"));
+	else
+		wipe_statusbar();
 
 	free(bytes);
 }

src/winio.c

@@ -1375,7 +1375,7 @@ int *parse_verbatim_kbinput(WINDOW *win, size_t *count)
 #ifndef NANO_TINY
 	/* When the window was resized, abort and return nothing. */
 	if (keycode == KEY_WINCH) {
-		*count = 0;
+		*count = 999;
 		return NULL;
 	}
 #endif
@@ -1397,6 +1397,12 @@ int *parse_verbatim_kbinput(WINDOW *win, size_t *count)
 			unicode = assemble_unicode(keycode);
 		}
 
+		if (keycode == KEY_WINCH) {
+			*count = 999;
+			free(yield);
+			return NULL;
+		}
+
 		/* For an invalid digit, discard its possible continuation bytes. */
 		if (unicode == INVALID_DIGIT)
 			while (key_buffer_len > 0 && 0x7F < *key_buffer && *key_buffer < 0xC0)
@@ -1480,9 +1486,11 @@ char *get_verbatim_kbinput(WINDOW *win, size_t *count)
 		keypad(bottomwin, TRUE);
 	}
 
-	for (size_t i = 0; i < *count; i++)
-		bytes[i] = (char)input[i];
-	bytes[*count] = '\0';
+	if (*count < 999) {
+		for (size_t i = 0; i < *count; i++)
+			bytes[i] = (char)input[i];
+		bytes[*count] = '\0';
+	}
 
 	free(input);