Everywhere: Document use of ladybird.py over ladybird.sh

Author: https://github.com/trflynn89
Commit: 7ce88eb4cd
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/4904
Reviewed-by: https://github.com/ADKaster

Tests/LibWeb/add_libweb_test.py

@@ -86,7 +86,7 @@ def create_test(test_name: str, test_type: str, is_async: bool = False) -> None:
         elif test_type == "Layout":
             input_boilerplate = generic_boilerplate
             expected_boilerplate = f"""run
- ./Meta/ladybird.sh run headless-browser --run-tests
+ ./Meta/ladybird.py run headless-browser --run-tests
  "${{LADYBIRD_SOURCE_DIR}}/Tests/LibWeb" --rebaseline -f {input_file}
 to produce the expected output for this test
 """