doc: add more info to fs.Dir and fix typos
Some doc bits / fixes which were missing from cbd8d715
Checklist
-
make -j4 test(UNIX), orvcbuild test(Windows) passes -
documentation is changed or added -
commit message follows commit guidelines
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Some doc bits / fixes which were missing from cbd8d715
make -j4 test (UNIX), or vcbuild test (Windows) passes