Documented missing properties; Whitespace and typo tomfoolery patched

Octokit/Models/Response/PullRequest.cs

@@ -14,8 +14,19 @@ namespace Octokit
         /// </summary>
         public int Number { get; set; }
 
+        /// <summary>
+        /// The URL for the pull request page.
+        /// </summary>
         public Uri HtmlUrl { get; set; }
+
+        /// <summary>
+        /// The URL for the pull request's diff (.diff) file.
+        /// </summary>
         public Uri DiffUrl { get; set; }
+
+        /// <summary>
+        /// The URL for the pull request's patch (.patch) file.
+        /// </summary>
         public Uri PatchUrl { get; set; }
     }
 }