Add explanation on how to pass arguments to view url

When overriding a view URL it might be interesting to know that you can use views' argument syntax to pass arguments within the URL. For example: node/$arg/myview. Since this can be easily confused with panels' own syntax, which is using % to denote args in panel URLs, it would be nice to add an explanation to the views pane configuration screens that this is in fact possible.

Attached patch tries to accomplish this in a translator-friendly way. If you feel the wording could be better then please change it.