Add a GitBlob.symbolInfo field to GraphQL
Created by: chrismwendt
Part of https://github.com/sourcegraph/sourcegraph/issues/35031
This adds a GitBlob.symbolInfo
field to GraphQL wired up to a dummy handler in the symbols service.
You'll see a // TODO find the symbol.
where the next chunk of logic will be added in the future.
Test plan
Automated tests