Search on the documentation page doesn't work

[jfharden]

When you use the search facility on the documentation page the results are found, but the links lead to 404 pages.

To replicate:

1. Browse to http://prometheus.github.io/client_java/
2. Enter CollectorRegistry in the search box
3. Click on the result "Types: io.prometheus.client.CollectorRegistry"
4. Land on a 404 page.

The URL it sends you to is: http://prometheus.github.io/client_java/undefined/io/prometheus/client/CollectorRegistry.html

Notice the /undefined/ part of the path. If you remove that the correct page is visited.