[Toybox] Sigh. I miss having useful standards bodies.

[Rob Landley]

I found the posix-2008 URL:
https://pubs.opengroup.org/onlinepubs/9699919799.2008edition/

And am seriously tempted to change all the command URLs to point there, and
modify the roadmap ala:

+<p>And although previous versions of Posix have their own
+stable URLs (where you can still find
+<a href=https://pubs.opengroup.org/onlinepubs/009695399/>SUSv3</a> and
+<a href=https://pubs.opengroup.org/onlinepubs/7990989775/>SUSv2</a>),
+the 2008 release of SUSv4 was replaced by a 2013 release also claiming
+to be SUSv4, then again by a 2018 release, all at the same URL. Similarly,
+the other version numbers claim not to have changed, but instead adopted some
+sort of "Windows 95" naming scheme ("Open Group Base Specifications Issue 7,
+2018 edition"). Since a moving target isn't a standard, we're mostly
+sticking with the 2008 version and ignoring whatever changes they make
+until they stop this forced-upgrade-behind-your
+back nonsense. Luckily you can still find the original content
+<a href=https://pubs.opengroup.org/onlinepubs/9699919799.2008edition/>here</a>.
+</p>

The main reason I _haven't_ changed the command URLs yet is it's longer and
would wrap past 80 chars more often. :P

Rob