Handle multi-byte: 2 codepoints single column

Very frequent with Devanagari scripts ('matra's)

nnn.c

@@ -1024,9 +1024,9 @@ xreadline(char *fname)
 	cleartimeout();
 
 	while (1) {
-		buf[len] = ' ';
+		clearprompt();
+		buf[len] = '\0';
 		mvaddnwstr(y, x, buf, len + 1);
-		move(y, x + pos);
 
 		if ((r = get_wch(ch)) != ERR) {
 			if (r == OK) {
@@ -2606,7 +2606,7 @@ nochange:
 			/* Check if another file with same name exists */
 			if (faccessat(fd, tmp, F_OK, AT_SYMLINK_NOFOLLOW) != -1) {
 				/* File with the same name exists */
-				printprompt("Press 'y' to overwrite: ");
+				printprompt("Press 'y' to overwrite");
 				cleartimeout();
 				r = getch();
 				settimeout();