Scope push to the default branch in copilot-setup-steps samples (#45823)

Co-authored-by: Claude <noreply@anthropic.com>

Author: brignano

content/copilot/how-tos/copilot-on-github/customize-copilot/customize-cloud-agent/customize-the-agent-environment.md

@@ -49,7 +49,7 @@ A `copilot-setup-steps.yml` file looks like a normal {% data variables.product.p
 > [!NOTE]
 > The `copilot-setup-steps.yml` workflow won't trigger unless it's present on your default branch.
 
-Here is a simple example of a `copilot-setup-steps.yml` file for a TypeScript project that clones the project, installs Node.js and downloads and caches the project's dependencies. You should customize this to fit your own project's language(s) and dependencies:
+Here is a simple example of a `copilot-setup-steps.yml` file for a TypeScript project that clones the project, installs Node.js and downloads and caches the project's dependencies. You should customize this to fit your own project, including its language(s), its dependencies, and the workflow triggers you need. For example, you wouldn't typically run on both `push` and `pull_request`.
 
 ```yaml copy
 name: "Copilot Setup Steps"