Fixes#13441
We're also starting on a glossary, doc/man7/openssl-glossary.pod,
where terms we use should be explained. There's no need to explain
terms as essays, but at least a few quick lines, and possibly a
reference to some external documentation.
Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/13581)
