[Cedar Doc Issue] Add examples for passing actions as entities in the input hierarchy

[JoshuaWilkes]

What were you trying to do?
I have tried to use this example for a cedar policy https://docs.cedarpolicy.com/policies/syntax-policy.html#term-parc-action

//matches any action in the hierarchy of the admin entity of type PhotoFlashRole
action in PhotoFlashRole::"admin"

When you write a policy like this you get an error like below:

expected an entity uid with the type `Action` but got `PhotoFlashRole::"admin"`. Action entities must have type `Action`

What is wrong and why?
I can find no other reference to being able to define actions as children of Entities so I believe that this is a mistake in the docs.

What do we need to do to fix this?
Edit: After some more testing, I think that the example needs to be changed to action in PhotoFlashRole::Action::"admin"

And a section should be added to the docs showing how you can supply actions as entities to create the hierarchy for policy evaluation.

[khieta]

Thanks for filing this issue! (And apologies for the delayed reply!) I've fixed the example you mentioned in #114.

However we still don't have examples for passing actions as entities in the input hierarchy (or mention of the fact that you don't need to do this with schema-based parsing), so I'll leave the issue open for now.