qa, doc: Fix comment

This change is a follow-up for:
- bitcoin/bitcoin#9956
- bitcoin/bitcoin#10096

Author: hebasto

test/functional/test_runner.py

@@ -783,8 +783,8 @@ def check_script_prefixes():
 def check_script_list(*, src_dir, fail_on_warn):
     """Check scripts directory.
 
-    Check that there are no scripts in the functional tests directory which are
-    not being run by pull-tester.py."""
+    Check that all python files in this directory are categorized
+    as a test script or meta script."""
     script_dir = src_dir + '/test/functional/'
     python_files = set([test_file for test_file in os.listdir(script_dir) if test_file.endswith(".py")])
     missed_tests = list(python_files - set(map(lambda x: x.split()[0], ALL_SCRIPTS + NON_SCRIPTS)))