docs: add missing xml comments

src/AnthropicClient/Models/ContentStopEventData.cs

@@ -2,8 +2,14 @@ using System.Text.Json.Serialization;
 
 namespace AnthropicClient.Models;
 
+/// <summary>
+/// Represents data for a content_block_stop event.
+/// </summary>
 public class ContentStopEventData : EventData
 {
+  /// <summary>
+  /// Gets the index of the content block.
+  /// </summary>
   public int Index { get; init; }
 
   [JsonConstructor]
@@ -11,6 +17,11 @@ public class ContentStopEventData : EventData
   {
   }
 
+  /// <summary>
+  /// Initializes a new instance of the <see cref="ContentStopEventData"/> class.
+  /// </summary>
+  /// <param name="index">The index of the content block.</param>
+  /// <returns>A new instance of the <see cref="ContentStopEventData"/> class.</returns>
   public ContentStopEventData(int index) : base(EventType.ContentBlockStop)
   {
     Index = index;