lib/irc: make isHighlight operate on messages

Makes it easier to re-use elsewhere.

lib/irc.js

@@ -219,7 +219,15 @@ function isWordBoundary(ch) {
 	}
 }
 
-export function isHighlight(text, nick) {
+export function isHighlight(msg, nick) {
+	if (msg.command != "PRIVMSG" && msg.command != "NOTICE") {
+		return false;
+	}
+	if (msg.prefix.name == nick) {
+		return false; // Our own messages aren't highlights
+	}
+
+	var text = msg.params[1];
 	while (true) {
 		var i = text.indexOf(nick);
 		if (i < 0) {