The link you attached still contains these:

> Don’t display an icon if you can’t find one that clearly represents the menu item

> Not all menu items need an icon. Be careful when adding icons for custom menu items to avoid confusion with other existing actions, and don’t add icons just for the sake of ornamentation.

> Instead of adding individual icons for each action, or reusing the same icon for all of them, establish a common theme with the symbol for the first item and rely on the menu item text to keep the remaining items distinct