docs: fix broken link to testing doc (apache#49442)

Author: kevinhongzl

dev/breeze/doc/05_test_commands.rst

@@ -68,7 +68,7 @@ To run the whole test class:
 You can re-run the tests interactively, add extra parameters to pytest  and modify the files before
 re-running the test to iterate over the tests. You can also add more flags when starting the
 ``breeze shell`` command when you run integration tests or system tests. Read more details about it
-in the `testing doc </contributing-docs/testing.rst>`_ where all the test types and information on how to run them are explained.
+in the `testing doc </contributing-docs/09_testing.rst>`_ where all the test types and information on how to run them are explained.
 
 This applies to all kind of tests - all our tests can be run using pytest.