Signal that the copilot-setup-steps samples are illustrative

Follow-up to issue 42379, per maintainer feedback. The sample workflow is meant
to illustrate rather than to be copied verbatim, but two things worked against
that.

Drop the `copy` annotation from the sample's fence in the reference article, so
it no longer renders a copy button.

In the "Improve a project" tutorial, extend the prompt that asks Copilot to
author the file, so the generated workflow gets a `workflow_dispatch` trigger
and doesn't run on both `push` and `pull_request`. Trim the extract below it to
the trigger and job name the surrounding sentence calls out, so it no longer
shows triggers the text never mentions.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FuL8Cm3afpXSBiiGnUo7FA

Author: claude

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

@@ -51,7 +51,7 @@ A `copilot-setup-steps.yml` file looks like a normal {% data variables.product.p
 
 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
+```yaml
 name: "Copilot Setup Steps"
 
 # Automatically run the setup steps when they are changed to allow for easy validation, and

content/copilot/tutorials/cloud-agent/improve-a-project.md

@@ -79,7 +79,7 @@ Creating this file is optional but is a good idea if you use {% data variables.c
 
    <!-- markdownlint-disable -->
    ```text copy
-   Analyze this repository to understand the dependencies that need to be installed on the development environment to work on the code in this repository. Using this information, and the details about the `copilot-setup-steps.yml` file that are given in https://docs.github.com/copilot/how-tos/use-copilot-agents/cloud-agent/customize-the-agent-environment, add a `.github/workflows/copilot-setup-steps.yml` to this repository. This Actions workflow file should install, in the development environment for {% data variables.copilot.copilot_cloud_agent %}, all of the dependencies necessary to work on the code in this repository. Make sure that the workflow job is named `copilot-setup-steps`.
+   Analyze this repository to understand the dependencies that need to be installed on the development environment to work on the code in this repository. Using this information, and the details about the `copilot-setup-steps.yml` file that are given in https://docs.github.com/copilot/how-tos/use-copilot-agents/cloud-agent/customize-the-agent-environment, add a `.github/workflows/copilot-setup-steps.yml` to this repository. This Actions workflow file should install, in the development environment for {% data variables.copilot.copilot_cloud_agent %}, all of the dependencies necessary to work on the code in this repository. Make sure that the workflow job is named `copilot-setup-steps`, and that the workflow includes a `workflow_dispatch` trigger so that it can be run manually. Choose any other triggers to suit this repository; there's no need to run on both `push` and `pull_request`.
    ```
    <!-- markdownlint-enable -->
 
@@ -97,12 +97,6 @@ Creating this file is optional but is a good idea if you use {% data variables.c
    ```yaml
    on:
      workflow_dispatch:
-     push:
-       paths:
-         - .github/workflows/copilot-setup-steps.yml
-     pull_request:
-       paths:
-         - .github/workflows/copilot-setup-steps.yml
 
    jobs:
      copilot-setup-steps: