Adding wording about default runner group (github#31734)

Co-authored-by: Martin Lopes <[email protected]>

Author: lkfortuna

content/actions/using-github-hosted-runners/using-larger-runners.md

@@ -12,6 +12,8 @@ versions:
 
 In addition to the [standard {% data variables.product.prodname_dotcom %}-hosted runners](/actions/using-github-hosted-runners/about-github-hosted-runners#supported-runners-and-hardware-resources), {% data variables.product.prodname_dotcom %} also offers customers on {% data variables.product.prodname_team %} and {% data variables.product.prodname_ghe_cloud %} plans a range of {% data variables.actions.hosted_runner %}s with more RAM and CPU. These runners are hosted by {% data variables.product.prodname_dotcom %} and have the runner application and other tools preinstalled.
 
+When {% data variables.actions.hosted_runner %}s are enabled for your organization, a default runner group is automatically created for you with a set of four pre-configured {% data variables.actions.hosted_runner %}s.
+
 When you add a {% data variables.actions.hosted_runner %} to an organization, you are defining a type of machine from a selection of available hardware specifications and operating system images. {% data variables.product.prodname_dotcom %} will then create multiple instances of this runner that scale up and down to match the job demands of your organization, based on the autoscaling limits you define.
 
 ## Machine specs for {% data variables.actions.hosted_runner %}s