Merge topic 'ctest-extra-submit'

9204721eda Help: Clarify 'ctest --extra-submit'
e7a90d0551 Help: Document CTEST_EXTRA_SUBMIT_FILES variable
123e002168 Help: Document CTEST_NOTES_FILES variable

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: buildbot <buildbot@kitware.com>
Merge-request: !10212