display information about current linking status in account maintenance

Author: DeinFreund

Zero-K.info/Views/Shared/UserDetail.cshtml

@@ -392,8 +392,14 @@
         <h3 class="js_expand">Account maintenance</h3>
         <div id="accountMaint" class="collapse width-90">
             <h4>Link Discord Account</h4>
+            @if (Global.Account.DiscordID.HasValue)
+            {
+                <div>
+                    Your account is currently linked to Discord ID @(Global.Account.DiscordID).
+                </div><br />
+            }
             <a href="@Global.Server.DiscordWebApi.GetAuthenticationURL(Global.AccountID)">Login with Discord</a> <br/>
-            <br />
+            
             <h4>Change password</h4>
             @if (!string.IsNullOrEmpty(Model.PasswordBcrypt))
             {
@@ -422,6 +428,7 @@
     }
     @if (Global.IsModerator && Global.AccountID == Model.AccountID)
     {
+        <br />
         <div class="admin">
             <h3>Admin extras</h3>
             <form action="@Url.Action("SetZklsMaxPlayers", "Admin")" method="post">

ZkLobbyServer/DiscordWebApi.cs

@@ -52,7 +52,7 @@ public async Task<bool> LinkAccount(string state, string code)
                 if (!userIds.TryGetValue(state, out accountId))
                 {
                     Trace.TraceWarning("Invalid state " + state);
-                    return;
+                    return false;
                 }
 
                 var request = new HttpRequestMessage(HttpMethod.Post, "https://discordapp.com/api/oauth2/token");