richedit: Prevent division by zero when 0-width border is used.

dlls/riched20/paint.c

@@ -290,7 +290,7 @@ static void ME_DrawRun(ME_Context *c, int x, int y, ME_DisplayItem *rundi, ME_Pa
 }
 
 static struct {unsigned width_num : 4, width_den : 4, pen_style : 4, dble : 1;} border_details[] = {
-  /* none */            {0, 0, PS_SOLID, FALSE},
+  /* none */            {0, 1, PS_SOLID, FALSE},
   /* 3/4 */             {3, 4, PS_SOLID, FALSE},
   /* 1 1/2 */           {3, 2, PS_SOLID, FALSE},
   /* 2 1/4 */           {9, 4, PS_SOLID, FALSE},