vim-patch:9.0.2145: wrong scrolling in insert mode with smoothscroll (#26375)

Problem:  Wrong scrolling in Insert mode with 'smoothscroll' at the
          bottom of the window.
Solution: Don't use set_topline() when 'smoothscroll' is set.

fixes: vim/vim#13612
closes: vim/vim#13613

5b4d1fcbf0

src/nvim/edit.c

@@ -444,8 +444,11 @@ static int insert_check(VimState *state)
   // is detected when the cursor column is smaller after inserting something.
   // Don't do this when the topline changed already, it has already been
   // adjusted (by insertchar() calling open_line())).
+  // Also don't do this when 'smoothscroll' is set, as the window should then
+  // be scrolled by screen lines.
   if (curbuf->b_mod_set
       && curwin->w_p_wrap
+      && !curwin->w_p_sms
       && !s->did_backspace
       && curwin->w_topline == s->old_topline
       && curwin->w_topfill == s->old_topfill) {