Link to civibuild page instead of buildkit site

As noted here https://github.com/civicrm/civicrm-buildkit/issues/333
I'm trying to move us away from using that dedicated site.

docs/testing/setup.md

@@ -2,10 +2,9 @@ The easiest way to get setup it to use buildkit. Buildkit will install the tools
 necessary for running the tests and creating local CiviCRM sites.
 
 You can download [CiviCRM buildkit](/tools/buildkit) which includes all the test tools.
-From there you can create a test site using [these instructions][buildkit-create].
+From there you can create a test site using [civibuild](/tools/civibuild).
 
-!!! info 
-    When writing new tests or making any changes make sure you run [civilint] 
+!!! info
+    When writing new tests or making any changes make sure you run [civilint]
     to ensure your changes match our coding style.
 
-[buildkit-create]: https://buildkit.civicrm.org/#/tutorials