Diagram/Doc : add limited support for sh:or with multiple sh:node

[tfrancart]

Use-case : a schema:contact can be either a schema:ContactPoint either a schema:PostalAdress See if we can either repeat the arrow, or group all the classes within a package and point to the package ?

[tfrancart]

Avec l'utilisation d'un "diamond" :

@startuml
class ContactPoint {
}

class PostalAddress {
}

class MEP {
}

<> diamond
MEP --> "contactPoint" diamond
diamond ... PostalAddress
diamond ... ContactPoint
@enduml

[tfrancart]

To be consistent we also need to support this in the documentation table generation : PropertyShapeDocumentation need to support references to multiple node shapes