vim-patch:9.0.1247: divide by zero with 'smoothscroll' set and a narrow window

Problem:    Divide by zero with 'smoothscroll' set and a narrow window.
Solution:   Bail out when the window is too narrow.

870219c58c

Co-authored-by: Bram Moolenaar <Bram@vim.org>

src/nvim/move.c

@@ -1475,6 +1475,9 @@ void adjust_skipcol(void)
   }
 
   int width1 = curwin->w_width - curwin_col_off();
+  if (width1 <= 0) {
+    return;  // no text will be displayed
+  }
   int width2 = width1 + curwin_col_off2();
   long so = get_scrolloff_value(curwin);
   long scrolloff_cols = so == 0 ? 0 : width1 + (so - 1) * width2;