Renamed GetContentTypeDescriptorsProxy()

Since `TopicRepositoryBase.GetContentTypeDescriptors(ContentTypeDescriptor)` has been marked as deprecated, in preference for the new `SetContentTypeDescriptors()` method (f1ade10), the `GetContentTypeDescriptorsProxy()` needs to be updated to call the new method.

While I was at it, I also deprecated the previous proxy itself, and introduced a new proxy that maps to the new name. This is perhaps not necessary since this is exclusively used by the `OnTopic.Tests`. The `StubTopicRepository` is publicly published via the `Ontopic.TestDoubles` package, however, so that it can be shared with other OnTopic related projects, such as `OnTopic-MVC`. This will help ensure compatibility with those projects.

Author: JeremyCaney

OnTopic.TestDoubles/StubTopicRepository.cs

@@ -180,8 +180,16 @@ public IEnumerable<AttributeValue> GetAttributesProxy(
     | METHOD: GET CONTENT TYPE DESCRIPTORS (PROXY)
     \-------------------------------------------------------------------------------------------------------------------------*/
     /// <inheritdoc cref="TopicRepositoryBase.GetContentTypeDescriptors(ContentTypeDescriptor)" />
+    [Obsolete("Deprecated. Instead, use the new SetContentTypeDescriptorsProxy(), which provides the same function.", false)]
     public ContentTypeDescriptorCollection GetContentTypeDescriptorsProxy(ContentTypeDescriptor topicGraph) =>
-      base.GetContentTypeDescriptors(topicGraph);
+      base.SetContentTypeDescriptors(topicGraph);
+
+    /*==========================================================================================================================
+    | METHOD: SET CONTENT TYPE DESCRIPTORS (PROXY)
+    \-------------------------------------------------------------------------------------------------------------------------*/
+    /// <inheritdoc cref="TopicRepositoryBase.SetContentTypeDescriptors(ContentTypeDescriptor)" />
+    public ContentTypeDescriptorCollection SetContentTypeDescriptorsProxy(ContentTypeDescriptor topicGraph) =>
+      base.SetContentTypeDescriptors(topicGraph);
 
     /*==========================================================================================================================
     | METHOD: GET CONTENT TYPE DESCRIPTOR (PROXY)

OnTopic.Tests/TopicRepositoryBaseTest.cs

@@ -321,7 +321,7 @@ public void GetContentTypeDescriptors_WithTopicGraph_ReturnsMergedContentTypes()
       var newContentType        = TopicFactory.Create("NewContentType", "ContentTypeDescriptor", rootContentType);
       var contentTypeCount      = contentTypes.Count;
 
-      _topicRepository.GetContentTypeDescriptorsProxy(rootContentType);
+      _topicRepository.SetContentTypeDescriptorsProxy(rootContentType);
 
       Assert.AreNotEqual<int>(contentTypeCount, contentTypes.Count);
       Assert.IsNotNull(contentTypes.Contains(newContentType));