Add other repos in bazelbuild to code search

[sluongng]

Hi folks,

I was wondering if we could setup code search to support the like of rules_go, rules_rust and rules_docker etc...

These repos are primarily written in go/rust which are the languages that Kythe already have a functioning extractor for.

Even without Kythe indexing, it would be nice just to get repos such as rules_python into https://cs.opensource.google/bazel so that we can search using regex.

Cheers.