kunit: Add documentation of --list_suites

Commit 60f3ada4174f ("kunit: Add --list_suites to show suites") introduced
the --list_suites option to kunit.py, but the update to the corresponding
run_wrapper documentation was omitted.

Add the missing description for --list_suites to keep the documentation in
sync with the tool's supported arguments.

Fixes: 60f3ada4174f ("kunit: Add --list_suites to show suites")
Signed-off-by: Ryota Sakamoto <[email protected]>
Reviewed-by: David Gow <[email protected]>
Signed-off-by: Shuah Khan <[email protected]>

Author: ryota-sakamoto

Documentation/dev-tools/kunit/run_wrapper.rst

@@ -336,6 +336,8 @@ command line arguments:
 - ``--list_tests_attr``: If set, lists all tests that will be run and all of their
   attributes.
 
+- ``--list_suites``: If set, lists all suites that will be run.
+
 Command-line completion
 ==============================