Adding comments explaining PullRequestId

Author: StanleyGoldman

src/GitHub.Exports/Models/CommentModel.cs

@@ -18,9 +18,12 @@ public class CommentModel
         public int DatabaseId { get; set; }
 
         /// <summary>
-        /// Gets the PullRequestId of the comment
+        /// Gets the PullRequestId of the comment.
         /// </summary>
         public int PullRequestId { get; set; }
+        // The GraphQL Api does not allow for deleting of pull request comments.
+        // REST Api must be used, and PullRequestId is needed to reload the pull request.
+        // This field should be removed with better GraphQL support.
 
         /// <summary>
         /// Gets the author of the comment.