missing detail on project website

[Doug McIlroy]

https://www.gnu.org/software/m4/m4.html under Mailing Lists says,
"see the details of each list for a link to the archives", but nowhere
does the page explicitly state where to find the details of m4-discuss.

One can guess the appropriate URL by analogy with other mailing lists.
It can also be found buried under the very specialized heading, Request
and Enhancement. Nevertheless, it deserves a direct descriptive sentence.

Doug McIlroy