Add MaxBitrate to the interface (#1861)

Co-authored-by: Quin Lynch <49576606+quinchs@users.noreply.github.com>

src/Discord.Net.Core/Entities/Guilds/IGuild.cs

@@ -313,6 +313,13 @@ namespace Discord
         ///     The approximate number of non-offline members in this guild.
         /// </returns>
         int? ApproximatePresenceCount { get; }
+        /// <summary>
+        ///     Gets the max bitrate for voice channels in this guild.
+        /// </summary>
+        /// <returns>
+        ///     A <see cref="int"/> representing the maximum bitrate value allowed by Discord in this guild.
+        /// </returns>
+        int MaxBitrate { get; }
 
         /// <summary>
         ///     Gets the preferred locale of this guild in IETF BCP 47

src/Discord.Net.Rest/Entities/Guilds/RestGuild.cs

@@ -86,6 +86,20 @@ namespace Discord.Rest
         /// <inheritdoc />
         public int? ApproximatePresenceCount { get; private set; }
         /// <inheritdoc/>
+        public int MaxBitrate
+        {
+            get
+            {
+                return PremiumTier switch
+                {
+                    PremiumTier.Tier1 => 128000,
+                    PremiumTier.Tier2 => 256000,
+                    PremiumTier.Tier3 => 384000,
+                    _ => 96000,
+                };
+            }
+        }
+        /// <inheritdoc />
         public NsfwLevel NsfwLevel { get; private set; }
         /// <inheritdoc />
         public bool IsBoostProgressBarEnabled { get; private set; }

src/Discord.Net.WebSocket/Entities/Guilds/SocketGuild.cs

@@ -185,24 +185,18 @@ namespace Discord.WebSocket
                 return id.HasValue ? GetVoiceChannel(id.Value) : null;
             }
         }
-        /// <summary>
+        /// <inheritdoc/>
-        ///     Gets the max bitrate for voice channels in this guild.
-        /// </summary>
-        /// <returns>
-        ///     A <see cref="int"/> representing the maximum bitrate value allowed by Discord in this guild.
-        /// </returns>
         public int MaxBitrate
         {
             get
             {
-                var maxBitrate = PremiumTier switch
+                return PremiumTier switch
                 {
                     PremiumTier.Tier1 => 128000,
                     PremiumTier.Tier2 => 256000,
                     PremiumTier.Tier3 => 384000,
                     _ => 96000,
                 };
-                return maxBitrate;
             }
         }
         /// <summary>