web: integrate `@sourcegraph/eslint-plugin-sourcegraph`
Created by: valerybugakov
Context
This PR migrates the existing check-help-links ESLint rule from the Sourcegraph repo to the codemod repo. The purpose of this work is to test the ESLint plugin integration. After that, the new custom rule will be added to the ESLint plugin that will warn on the usage of specific React elements. E.g., react/warn-elements.
It's not currently possible to reuse the react/forbid-elements rule for warnings because of the limitations of the ESLint API. It would allow us to warn on the usage of patterns that we want to deprecate. E.g., while the Input migration is not yet completed, we can ask engineers to use the Input component over the input element today.
The check-help-links rule implementation PR.
Test plan
yarn lint:js:all should pass locally
App preview:
Check out the client app preview documentation to learn more.