- Remove pylint warning suppression from SHAKE-128 hexdigest calls; these
  are no longer needed as of astroid 2.12.12. For background, see issue
  <https://github.com/PyCQA/pylint/issues/4039>. Also, correct a comment
  that referred to SHAKE-256 instead of SHAKE-128.
- Replace "released" with "beta" in several places where there was a copy
  & paste error in dark_lang. Add mention of `beta_lang` to a docstring
  where it was omitted.
- Remove comment regarding Mongo startup; the code it referred to has since
  been removed.
- Fix typos.