Errata for hyperspec?

[Pierpaolo Bernardi]

The item discussed in
https://groups.google.com/forum/#!searchin/comp.lang.lisp/pierpaolo$20bernardi$20format$20sign%7Csort:date/comp.lang.lisp/9zUNvDRYvBY/_FKFO8hc4zsJ
needs a clarification, and I don't see it listed in the wiki page.
Can somebody add it, or should I do it myself?  I lost track of what
wiki page is the currently cared for one.

TL;DR:

(format nil "~@D" 0)    ==>  ? (currently unclear)

KMP wrote in that thread: "I would argue for clarifying this as "+0"
in a future standard.". Everybody else seemed to substantially agree.