Better PropTypes.node input

[lucasconstantino]

I tried to find a related issue, but could not. Currently, any property with type "node" is rendered with an input that seems like a text area, but nothing I put on it has any effect in the component view. How is this input supposed to work? PropTypes.node is indeed tricky as it accepts pretty much anything that could be rendered... you guys think we could build a composed input for that? Maybe first select from node types, then show the type's specific input, such as string, element, etc.