squirrel: Add boilerplate for tree-sitter traversals
Created by: chrismwendt
Part of https://github.com/sourcegraph/sourcegraph/issues/35031
- Adds a test framework for defs
- Fills in the HTTP handler
- Adds a stub
getDef()
method
Test plan
N/A
Created by: chrismwendt
Part of https://github.com/sourcegraph/sourcegraph/issues/35031
getDef()
methodN/A