Expand upon test channels (#4655)

Available test channels:

- `$$$` - Fill up scrollback (1000 messages), then add a new message every 500ms
- `$$$:e` - Add a new message every 500ms
- `$$$$` - Fill up scrollback (1000 messages), then add a new message every 250ms
- `$$$$:e` - Add a new message every 250ms
- `$$$$$` - Fill up scrollback (1000 messages), then add a new message every 100ms
- `$$$$$:e` - Add a new message every 100ms
- `$$$$$$` - Fill up scrollback (1000 messages), then add a new message every 50ms
- `$$$$$$:e` - Add a new message every 50ms
- `$$$$$$$` - Fill up scrollback (1000 messages), then add a new message every 25ms
- `$$$$$$$:e` - Add a new message every 25ms

src/singletons/WindowManager.cpp

@@ -631,6 +631,10 @@ void WindowManager::encodeChannel(IndirectChannel channel, QJsonObject &obj)
             }
         }
         break;
+        case Channel::Type::Misc: {
+            obj.insert("type", "misc");
+            obj.insert("name", channel.get()->getName());
+        }
     }
 }
 
@@ -676,6 +680,10 @@ IndirectChannel WindowManager::decodeChannel(const SplitDescriptor &descriptor)
         return Irc::instance().getOrAddChannel(descriptor.server_,
                                                descriptor.channelName_);
     }
+    else if (descriptor.type_ == "misc")
+    {
+        return app->twitch->getChannelOrEmpty(descriptor.channelName_);
+    }
 
     return Channel::getEmpty();
 }