lint: Discord Namespace Clean-up (#1185)

* Remove RpcException

* Move RestConnection to Discord.Net.Rest

* Remove RpcVirtualMessageChannel

* Move REST objects to Discord.Net.Rest

* Fix Discord.Rest namespace

src/Discord.Net.Core/Net/RpcException.cs

@@ -1,17 +0,0 @@
-using System;
-
-namespace Discord
-{
-    public class RpcException : Exception
-    {
-        public int ErrorCode { get; }
-        public string Reason { get; }
-
-        public RpcException(int errorCode, string reason = null)
-            : base($"The server sent error {errorCode}{(reason != null ? $": \"{reason}\"" : "")}")
-        {
-            ErrorCode = errorCode;
-            Reason = reason;
-        }
-    }
-}

src/Discord.Net.Rest/Entities/Channels/RpcVirtualMessageChannel.cs

@@ -1,110 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Diagnostics;
-using System.IO;
-using System.Linq;
-using System.Threading.Tasks;
-
-namespace Discord.Rest
-{
-    [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
-    internal class RestVirtualMessageChannel : RestEntity<ulong>, IMessageChannel
-    {
-        public DateTimeOffset CreatedAt => SnowflakeUtils.FromSnowflake(Id);
-        public string Mention => MentionUtils.MentionChannel(Id);
-
-        internal RestVirtualMessageChannel(BaseDiscordClient discord, ulong id)
-            : base(discord, id)
-        {
-        }
-        internal static RestVirtualMessageChannel Create(BaseDiscordClient discord, ulong id)
-        {
-            return new RestVirtualMessageChannel(discord, id);
-        }
-
-        public Task<RestMessage> GetMessageAsync(ulong id, RequestOptions options = null)
-            => ChannelHelper.GetMessageAsync(this, Discord, id, options);
-        public IAsyncEnumerable<IReadOnlyCollection<RestMessage>> GetMessagesAsync(int limit = DiscordConfig.MaxMessagesPerBatch, RequestOptions options = null)
-            => ChannelHelper.GetMessagesAsync(this, Discord, null, Direction.Before, limit, options);
-        public IAsyncEnumerable<IReadOnlyCollection<RestMessage>> GetMessagesAsync(ulong fromMessageId, Direction dir, int limit = DiscordConfig.MaxMessagesPerBatch, RequestOptions options = null)
-            => ChannelHelper.GetMessagesAsync(this, Discord, fromMessageId, dir, limit, options);
-        public IAsyncEnumerable<IReadOnlyCollection<RestMessage>> GetMessagesAsync(IMessage fromMessage, Direction dir, int limit = DiscordConfig.MaxMessagesPerBatch, RequestOptions options = null)
-            => ChannelHelper.GetMessagesAsync(this, Discord, fromMessage.Id, dir, limit, options);
-        public Task<IReadOnlyCollection<RestMessage>> GetPinnedMessagesAsync(RequestOptions options = null)
-            => ChannelHelper.GetPinnedMessagesAsync(this, Discord, options);
-
-        public Task<RestUserMessage> SendMessageAsync(string text = null, bool isTTS = false, Embed embed = null, RequestOptions options = null)
-            => ChannelHelper.SendMessageAsync(this, Discord, text, isTTS, embed, options);
-        public Task<RestUserMessage> SendFileAsync(string filePath, string text, bool isTTS = false, Embed embed = null, RequestOptions options = null)
-            => ChannelHelper.SendFileAsync(this, Discord, filePath, text, isTTS, embed, options);
-        public Task<RestUserMessage> SendFileAsync(Stream stream, string filename, string text, bool isTTS = false, Embed embed = null, RequestOptions options = null)
-
-            => ChannelHelper.SendFileAsync(this, Discord, stream, filename, text, isTTS, embed, options);
-
-        /// <inheritdoc />
-        public Task DeleteMessageAsync(ulong messageId, RequestOptions options = null)
-            => ChannelHelper.DeleteMessageAsync(this, messageId, Discord, options);
-        /// <inheritdoc />
-        public Task DeleteMessageAsync(IMessage message, RequestOptions options = null)
-            => ChannelHelper.DeleteMessageAsync(this, message.Id, Discord, options);
-
-        /// <inheritdoc />
-        public Task TriggerTypingAsync(RequestOptions options = null)
-            => ChannelHelper.TriggerTypingAsync(this, Discord, options);
-        /// <inheritdoc />
-        public IDisposable EnterTypingState(RequestOptions options = null)
-            => ChannelHelper.EnterTypingState(this, Discord, options);
-
-        private string DebuggerDisplay => $"({Id}, Text)";
-
-        //IMessageChannel
-        async Task<IMessage> IMessageChannel.GetMessageAsync(ulong id, CacheMode mode, RequestOptions options)
-        {
-            if (mode == CacheMode.AllowDownload)
-                return await GetMessageAsync(id, options).ConfigureAwait(false);
-            else
-                return null;
-        }
-        IAsyncEnumerable<IReadOnlyCollection<IMessage>> IMessageChannel.GetMessagesAsync(int limit, CacheMode mode, RequestOptions options)
-        {
-            if (mode == CacheMode.AllowDownload)
-                return GetMessagesAsync(limit, options);
-            else
-                return AsyncEnumerable.Empty<IReadOnlyCollection<IMessage>>();
-        }
-        IAsyncEnumerable<IReadOnlyCollection<IMessage>> IMessageChannel.GetMessagesAsync(ulong fromMessageId, Direction dir, int limit, CacheMode mode, RequestOptions options)
-        {
-            if (mode == CacheMode.AllowDownload)
-                return GetMessagesAsync(fromMessageId, dir, limit, options);
-            else
-                return AsyncEnumerable.Empty<IReadOnlyCollection<IMessage>>();
-        }
-        IAsyncEnumerable<IReadOnlyCollection<IMessage>> IMessageChannel.GetMessagesAsync(IMessage fromMessage, Direction dir, int limit, CacheMode mode, RequestOptions options)
-        {
-            if (mode == CacheMode.AllowDownload)
-                return GetMessagesAsync(fromMessage, dir, limit, options);
-            else
-                return AsyncEnumerable.Empty<IReadOnlyCollection<IMessage>>();
-        }
-        async Task<IReadOnlyCollection<IMessage>> IMessageChannel.GetPinnedMessagesAsync(RequestOptions options)
-            => await GetPinnedMessagesAsync(options).ConfigureAwait(false);
-
-        async Task<IUserMessage> IMessageChannel.SendFileAsync(string filePath, string text, bool isTTS, Embed embed, RequestOptions options)
-            => await SendFileAsync(filePath, text, isTTS, embed, options);
-
-        async Task<IUserMessage> IMessageChannel.SendFileAsync(Stream stream, string filename, string text, bool isTTS, Embed embed, RequestOptions options)
-            => await SendFileAsync(stream, filename, text, isTTS, embed, options).ConfigureAwait(false);
-        async Task<IUserMessage> IMessageChannel.SendMessageAsync(string text, bool isTTS, Embed embed, RequestOptions options)
-            => await SendMessageAsync(text, isTTS, embed, options).ConfigureAwait(false);
-
-        //IChannel
-        string IChannel.Name => 
-            throw new NotSupportedException();
-
-        IAsyncEnumerable<IReadOnlyCollection<IUser>> IChannel.GetUsersAsync(CacheMode mode, RequestOptions options) => 
-            throw new NotSupportedException();
-
-        Task<IUser> IChannel.GetUserAsync(ulong id, CacheMode mode, RequestOptions options) => 
-            throw new NotSupportedException();
-    }
-}

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

@@ -1,7 +1,7 @@
 using System.Diagnostics;
 using Model = Discord.API.GuildEmbed;
 
-namespace Discord
+namespace Discord.Rest
 {
     [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
     public struct RestGuildEmbed

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

@@ -2,7 +2,7 @@ using Discord.Rest;
 using System.Diagnostics;
 using Model = Discord.API.VoiceRegion;
 
-namespace Discord
+namespace Discord.Rest
 {
     /// <summary>
     ///     Represents a REST-based voice region.

src/Discord.Net.Rest/Entities/Users/RestConnection.cs

@@ -3,7 +3,7 @@ using System.Collections.Immutable;
 using System.Diagnostics;
 using Model = Discord.API.Connection;
 
-namespace Discord
+namespace Discord.Rest
 {
     [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
     public class RestConnection : IConnection