Change to using ToRepositoryUrl from UriString

Author: jcansdale

src/GitHub.App/ViewModels/GitHubPane/PullRequestDetailViewModel.cs

@@ -329,7 +329,7 @@ public async Task InitializeAsync(
                 LocalRepository = localRepository;
                 RemoteRepositoryOwner = owner;
                 Number = number;
-                WebUrl = ToPullRequestUrl(localRepository.CloneUrl.Host, owner, localRepository.Name, number);
+                WebUrl = localRepository.CloneUrl.ToRepositoryUrl(owner);
                 modelService = await modelServiceFactory.CreateAsync(connection);
 
                 await Refresh();
@@ -345,12 +345,6 @@ public async Task InitializeAsync(
             }
         }
 
-        static Uri ToPullRequestUrl(string host, string owner, string repositoryName, int number)
-        {
-            var url = string.Format(CultureInfo.InvariantCulture, "https://{0}/{1}/{2}/pull/{3}", host, owner, repositoryName, number);
-            return new Uri(url);
-        }
-
         void RefreshIfActive(object sender, EventArgs e)
         {
             if (active)