Add keyPath initializer for Persisted<LinkingObjects>

CHANGELOG.md

@@ -1,7 +1,8 @@
 x.y.z Release notes (yyyy-MM-dd)
 =============================================================
 ### Enhancements
-* None.
+* Add support for KeyPath initializiation for LinkingObjects declared with @Persisted: 
+  `@Persisted(originProperty: \.dogs) var persons: LinkingObjects<Person>
 
 ### Fixed
 * <How to hit and notice issue? what was the impact?> ([#????](https://github.com/realm/realm-swift/issues/????), since v?.?.?)

RealmSwift/PersistedProperty.swift

@@ -361,6 +361,9 @@ extension Persisted where Value: LinkingObjectsProtocol {
     public init(originProperty: String) {
         self.init(wrappedValue: Value(fromType: Value.Element.self, property: originProperty))
     }
+    public init<V>(originProperty: KeyPath<Value.Element, V?>) where Value.Element: ObjectBase, V: ObjectBase {
+        self.init(wrappedValue: Value(fromType: Value.Element.self, property: _name(for: originProperty)))
+    }
 }
 extension LinkingObjects: LinkingObjectsProtocol {}
 

RealmSwift/Tests/ModernTestObjects.swift

@@ -156,7 +156,7 @@ class ModernAllTypesObject: Object {
     @Persisted var mapOptObjectId: Map<String, ObjectId?>
     @Persisted var mapOptUuid: Map<String, UUID?>
 
-    @Persisted(originProperty: "objectCol")
+    @Persisted(originProperty: \.objectCol)
     var linkingObjects: LinkingObjects<ModernAllTypesObject>
 }