Feature Request: Show what doctypes can be children of others

[steroberts89]

Maybe some diagram way of showing how document type can be used and as children as what?

could get interesting with any circular references.

So it could use the "allow at root" to know which documents are at the start of the tree and then show the doctypes which can be put under that etc

[naepalm]

@steroberts89 Brilliant. Definitely doable.