As noted in the /help/ docs, this feature isn't fully implemented yet.
However, it's useful to merge this documentation, which explains how the
feature will work, to help make sure we've thought through all the details
around how this feature should work and be presented to users as we
plan to final changes to implement it.
This commit does not edit other help pages to reflect the existence of
web public streams.
Co-authored-by: Tim Abbott <tabbott@zulip.com>