codeintel: expose code intel info for `GitBlob`
Created by: Strum355
Closes https://github.com/sourcegraph/sourcegraph/issues/31073 Reliant on https://github.com/sourcegraph/go-ctags/pull/7
Test plan
Tested by hand in the API console. The brunt of the work is done in symbols service/go-ctags, and we dont have a great way of testing symbols service interfacing yet, sot his has been mostly manually tested