I can see how the current phrasing gives one pause, and might seem incomplete, but it is not incorrect. The sense of
Additionally, users can run one of ::
<yourscript> -h
<yourscript> --help
and optparse will ...
is "Additionally, users can run one of ``<yourscript> -h`` or ``<yourscript> --help`` and optparse will ...". I personally prefer this running text form with in-line code markup to the block form. What do you think?
If we keep the block form, I slightly prefer 'one of the following' to 'one of the next lines' but cannot say why.