Change intro portion of Testing page (#48692)

* Change intro portion of Testing page

docs/docsite/rst/dev_guide/testing.rst

@@ -7,14 +7,17 @@ Testing Ansible
 .. contents:: Topics
    :local:
 
-Introduction
-============
 
-This document describes:
+Why test your Ansible contributions?
+====================================
+
+If you're a developer, one of the most valuable things you can do is to look at GitHub issues and help fix bugs, since bug-fixing is almost always prioritized over feature development.  Even for non-developers, helping to test pull requests for bug fixes and features is still immensely valuable.
+
+Ansible users who understand how to write playbooks and roles should be able to test their work.  GitHub pull requests will automatically run a variety of tests (e.g., Shippable) that show bugs in action.  However, contributors must also test their work outside of the automated GitHub checks and show evidence of these tests in the PR to ensure that their work will be more likely to be reviewed and merged.
+
+Read on to learn how Ansible is tested, how to test your contributions locally, and how to extend testing capabilities.
+
 
-* how Ansible is tested
-* how to test Ansible locally
-* how to extend the testing capabilities
 
 Types of tests
 ==============
@@ -212,4 +215,3 @@ Want to know more about testing?
 
 If you'd like to know more about the plans for improving testing Ansible then why not join the
 `Testing Working Group <https://github.com/ansible/community/blob/master/meetings/README.md>`_.
-