patch 8.2.1694: compiler warning for loss if data

Problem:    Compiler warning for loss if data.
Solution:   Add typecast.
diff --git a/src/ops.c b/src/ops.c
index d572940..99388a6 100644
--- a/src/ops.c
+++ b/src/ops.c
@@ -2840,7 +2840,8 @@
 	    // Delete the one character before the insert.
 	    curwin->w_cursor = save_pos;
 	    (void)del_char(FALSE);
-	    curwin->w_cursor.col = STRLEN(ml_get_curline()) - bytes_after;
+	    curwin->w_cursor.col = (colnr_T)(STRLEN(ml_get_curline())
+								- bytes_after);
 	    --todel;
 	}
 	while (todel-- > 0)