Add documentation for `Padder` widget

[patriksvensson]

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Please upvote 👍 this issue if you are interested in it.

[Elisha-Aguilera]

I can work on this item, as well as Issue #752; three documentation items, and if you have any more good technical issues, feel free to share with the team.

[FrankRay78]

Hello @Elisha-Aguilera, just checking in to see how you are going and whether you are still working on #752, #753, #754 ?