Render voice channel mentions

Closes #636

DiscordChatExporter.Core/Discord/Data/Channel.cs

@@ -21,6 +21,8 @@ namespace DiscordChatExporter.Core.Discord.Data
             ChannelType.GuildNews or
             ChannelType.GuildStore;
 
+        public bool IsVoiceChannel => !IsTextChannel;
+
         public Snowflake GuildId { get; }
 
         public ChannelCategory Category { get; }

DiscordChatExporter.Core/Discord/DiscordClient.cs

@@ -142,10 +142,6 @@ namespace DiscordChatExporter.Core.Discord
 
                     var channel = Channel.Parse(channelJson, category, position);
 
-                    // We are only interested in text channels
-                    if (!channel.IsTextChannel)
-                        continue;
-
                     position++;
 
                     yield return channel;

DiscordChatExporter.Core/Exporting/Writers/MarkdownVisitors/HtmlMarkdownVisitor.cs

@@ -99,11 +99,12 @@ namespace DiscordChatExporter.Core.Exporting.Writers.MarkdownVisitors
             else if (mention.Kind == MentionKind.Channel)
             {
                 var channel = mentionId?.Pipe(_context.TryGetChannel);
+                var symbol = channel?.IsVoiceChannel == true ? "🔊" : "#";
                 var name = channel?.Name ?? "deleted-channel";
 
                 _buffer
                     .Append("<span class=\"mention\">")
-                    .Append("#").Append(HtmlEncode(name))
+                    .Append(symbol).Append(HtmlEncode(name))
                     .Append("</span>");
             }
             else if (mention.Kind == MentionKind.Role)

DiscordChatExporter.Core/Exporting/Writers/MarkdownVisitors/PlainTextMarkdownVisitor.cs

@@ -43,6 +43,10 @@ namespace DiscordChatExporter.Core.Exporting.Writers.MarkdownVisitors
                 var name = channel?.Name ?? "deleted-channel";
 
                 _buffer.Append($"#{name}");
+
+                // Voice channel marker
+                if (channel?.IsVoiceChannel == true)
+                    _buffer.Append(" [voice]");
             }
             else if (mention.Kind == MentionKind.Role)
             {

DiscordChatExporter.Core/Markdown/Parsing/MarkdownParser.cs

@@ -135,7 +135,7 @@ namespace DiscordChatExporter.Core.Markdown.Parsing
 
         // Capture <#123456>
         private static readonly IMatcher<MarkdownNode> ChannelMentionNodeMatcher = new RegexMatcher<MarkdownNode>(
-            new Regex("<#(\\d+)>", DefaultRegexOptions),
+            new Regex("<#!?(\\d+)>", DefaultRegexOptions),
             (_, m) => new MentionNode(m.Groups[1].Value, MentionKind.Channel)
         );