Fix SSBC executor broken links (#1374)

<!-- Explain the changes introduced in your PR -->

## Pull Request approval

You will need to get your PR approved by at least one member of the
Sourcegraph team. For reviews of docs formatting, styles, and component
usage, please tag the docs team via the #docs Slack channel.

Author: gabtorre

docs/admin/executors/deploy_executors_kubernetes.mdx

@@ -62,7 +62,7 @@ Native Kubernetes Executors can be deployed via either the `sourcegraph-executor
 
 ### Steps
 
-1. If you are deploying Executors for processing Batch Changes, set the `native-ssbc-execution` [feature flag](/admin/executors/native_execution#enable)
+1. If you are deploying Executors for processing Batch Changes, enable the `native-ssbc-execution` feature flag in **Site admin > Feature flags** by creating a Boolean feature flag with the value set to `true`
 2. Configure the following environment variables on the Executor Deployment:
     1. `EXECUTOR_FRONTEND_URL` should match the URL of your Sourcegraph instance
     2. `EXECUTOR_FRONTEND_PASSWORD` should match the `executors.accessToken` key in the Sourcegraph instance's site configuration
@@ -123,11 +123,6 @@ Environment.
 - Disable access to internal resources.
 - Disable access to `169.254.169.254` (AWS / GCP Instance Metadata Service).
 
-### Batch Changes
-
-To run [Batch Changes](/batch-changes/) on
-Kubernetes, [native Server-Side Batch Changes](/admin/executors/native_execution) must be enabled.
-
 ### Docker Image
 
 The Executor Docker image is available on Docker Hub at [`sourcegraph/executor-kubernetes`](https://hub.docker.com/r/sourcegraph/executor-kubernetes/tags).