Add DisplayName property to IGuildUser. (#2107)

src/Discord.Net.WebSocket/Entities/Users/SocketGuildUser.cs

@@ -30,6 +30,8 @@ namespace Discord.WebSocket
         /// </summary>
         public SocketGuild Guild { get; }
         /// <inheritdoc />
+        public string DisplayName => Nickname ?? Username;
+        /// <inheritdoc />
         public string Nickname { get; private set; }
         /// <inheritdoc/>
         public string GuildAvatarId { get; private set; }

src/Discord.Net.WebSocket/Entities/Users/SocketThreadUser.cs

@@ -29,6 +29,10 @@ namespace Discord.WebSocket
         public DateTimeOffset? JoinedAt
             => GuildUser.JoinedAt;
 
+        /// <inheritdoc/>
+        public string DisplayName
+            => GuildUser.Nickname ?? GuildUser.Username;
+
         /// <inheritdoc/>
         public string Nickname
             => GuildUser.Nickname;

src/Discord.Net.WebSocket/Entities/Users/SocketWebhookUser.cs

@@ -63,6 +63,8 @@ namespace Discord.WebSocket
         /// <inheritdoc />
         DateTimeOffset? IGuildUser.JoinedAt => null;
         /// <inheritdoc />
+        string IGuildUser.DisplayName => null;
+        /// <inheritdoc />
         string IGuildUser.Nickname => null;
         /// <inheritdoc />
         string IGuildUser.GuildAvatarId => null;