Reintroduced Load() overload as [Obsolete]

The `Load(uniqueKey, isRecursive)` overload was updated to include the `referenceTopic` parameter. By reintroducing the original overload, we provide instructions to callers of the original method signature. In practice, we don't expect this to be a common scenario, as it is generally expected that loads will be recursive.

Unfortunately, an `[Obsolete[]` member of an interface still needs to be implemented on each implementation of that interface. As such, we won't want to persist these for long after the migration to OnTopic 5.0.0. That said, fortunately, we expect all implementations of `ITopicRepository` to implement `ObservableTopicRepository` as a base class and, therefore, can implement these in that one location in order to cover all derived types (e.g., `SqlTopicRepository`, `CachedTopicRepository`, &c.)

Author: JeremyCaney

OnTopic/Repositories/ITopicRepository.cs

@@ -106,6 +106,10 @@ public interface ITopicRepository {
     /// <returns>A topic object.</returns>
     Topic? Load(string? uniqueKey = null, Topic? referenceTopic = null, bool isRecursive = true);
 
+    /// <inheritdoc cref="Load(Int32, Topic?, Boolean)"/>
+    [Obsolete("This overload has been removed in preference for Load(string, Topic, Boolean).")]
+    Topic? Load(string? uniqueKey, bool isRecursive);
+
     /// <summary>
     ///   Loads a specific version of a <see cref="Topic"/> based on its <paramref name="topicId"/> and <paramref name="version
     ///   "/>.

OnTopic/Repositories/ObservableTopicRepository.cs

@@ -208,6 +208,10 @@ public event EventHandler<TopicRenameEventArgs>? TopicRenamed {
     /// <inheritdoc />
     public abstract Topic? Load(string? uniqueKey = null, Topic? referenceTopic = null, bool isRecursive = true);
 
+    /// <inheritdoc cref="Load(Int32, Topic?, Boolean)"/>
+    [Obsolete("This overload has been removed in preference for Load(string, Topic, Boolean).")]
+    public Topic? Load(string? uniqueKey, bool isRecursive) => throw new NotImplementedException();
+
     /// <inheritdoc />
     public abstract Topic? Load(Topic topic, DateTime version);