AK: Make quick_sort() a little more ergonomic

Now it actually defaults to "a < b" comparison, instead of forcing you
to provide a trivial less-than comparator. Also you can pass in any
collection type that has .begin() and .end() and we'll sort it for you.

Applications/IRCClient/IRCClient.cpp

@@ -542,7 +542,7 @@ void IRCClient::handle_rpl_namreply(const Message& msg)
     auto& channel = ensure_channel(channel_name);
     auto members = msg.arguments[3].split(' ');
 
-    quick_sort(members.begin(), members.end(), [](auto& a, auto& b) {
+    quick_sort(members, [](auto& a, auto& b) {
         return strcasecmp(a.characters(), b.characters()) < 0;
     });