Update guidance on icon colors for the ActionMenu items

[cmwinters]

There's some ambiguity about whether or not we should recommend different colors for leading icons in the ActionMenu.

This PR updates the guidance to recommend against using colored icons for anything other than destructive actions.

[Lobesitdoll]

I Agree , keep it simple .

[maximedegreve]

Thank you for adding this @cmwinters.

This looks good but I have a few improvements we could make.

• Could you make the dropdown less wide since the menu should never go this wide for the content it currently holds. (Example).
• Could we find a more realistic example? Actions currently don't have the ability to be forked, sponsored or starred. If Actions refers a generic list of actions and not the product then a 3 dot or cog icon button would make more sense.
• We also tend to group edit actions. Therefore adding a separator before the delete action would make sense here. (example)