Change doc URL from beta to non-beta (closes #908)
Change doc URL from beta to non-beta (closes #908)

I don't see any reason why the reader should be directed to the beta
docs instead of the current ones.

shils/incubator-groovy,shils/incubator-groovy,shils/groovy,paulk-asert/groovy,shils/groovy,shils/groovy,shils/incubator-groovy,paulk-asert/incubator-groovy,paulk-asert/incubator-groovy,apache/groovy,jwagenleitner/groovy,jwagenleitner/incubator-groovy,jwagenleitner/incubator-groovy,apache/groovy,armsargis/groovy,paulk-asert/groovy,apache/incubator-groovy,jwagenleitner/incubator-groovy,jwagenleitner/groovy,paulk-asert/groovy,shils/incubator-groovy,paulk-asert/incubator-groovy,paulk-asert/incubator-groovy,apache/groovy,jwagenleitner/groovy,apache/incubator-groovy,apache/incubator-groovy,paulk-asert/groovy,paulk-asert/incubator-groovy,armsargis/groovy,armsargis/groovy,armsargis/groovy,jwagenleitner/incubator-groovy,apache/incubator-groovy,apache/groovy,jwagenleitner/groovy,shils/groovy