Expand comment explaining dummy memray options (#15539)

Author: iliakur

datadog_checks_dev/datadog_checks/dev/plugin/pytest.py

@@ -353,8 +353,9 @@ def pytest_addoption(parser):
     parser.addoption("--run-latest-metrics", action="store_true", default=False, help="run check_metrics tests")
 
     if PY2:
-        # Add a dummy memray options to make it possible to run memray with `ddev test --memray <integration>`
-        # only on py3 environments
+        # Add dummy memray options to make it possible to run memray with `ddev test --memray <integration>`
+        # in both py2 and 3 environments. In py2 the option is simply ignored, see pytest_collection_modifyitems.
+        # In py3 the option enables the memray plugin.
         parser.addoption("--memray", action="store_true", default=False, help="Dummy parameter for memray")
         parser.addoption(
             "--hide-memray-summary",