Documentation for router operator could use some cleanup

[Dylan-M]

1. Only the alias ($.) for $record is documented, while $resources, $labels, and the full $record are not documented at all, nor have any examples using.
2. The Route with a default example doesn't actually use default: , and instead uses a route with expr: 'true'. While this would work, it seems poor form.
3. No examples of routes with added labels to show syntax of that part of route configuration