Skip implementing Related if the same related entity is being referenced by a conjunct relation

[billy1624]

PR Info

• Closes > 0.10.2: error[E0119]: conflicting implementations of trait #1287

Bug Fixes

The original bug description: #1287 (comment)

• Skip implementing the direct Related if a many-to-many with intermediate entity exists.

// Skip implementation of ths
impl Related<super::baker::Entity> for Entity {
    fn to() -> RelationDef {
        Relation::Baker.def()
    }
}

// Keep this
impl Related<super::baker::Entity> for Entity {
    fn to() -> RelationDef {
        super::cakes_bakers::Relation::Baker.def()
    }
    fn via() -> Option<RelationDef> {
        Some(super::cakes_bakers::Relation::Cake.def().rev())
    }
}