Fetch read marker before backlog for user targets

lib/client.js

@@ -720,6 +720,11 @@ export default class Client extends EventTarget {
 		return chanTypes.indexOf(name[0]) >= 0;
 	}
 
+	isNick(name) {
+		// A dollar sign is used for server-wide broadcasts
+		return !this.isServer(name) && !this.isChannel(name) && !name.startsWith('$');
+	}
+
 	setPingInterval(sec) {
 		clearInterval(this.pingIntervalID);
 		this.pingIntervalID = null;