bug#30660: mention describe-bindings on (info "(emacs) Keymaps")

[Eli Zaretskii]

> From: Stefan Kangas <stefan@marxist.se>
> Cc: larsi@gnus.org,  30660@debbugs.gnu.org,  jidanni@jidanni.org
> Date: Mon, 11 Nov 2019 16:04:10 +0100
> 
> In the attached patch, I've added it to the user manual in addition to
> the elisp manual.  I followed the example of describe-bindings which
> is documented in both.

I'd prefer to have just one description in the user manual, and have a
cross-reference in the ELisp manual which points to that.  I don't
know why describe-bindings was documented in both manuals, and see no
reason to continue doing so (the ELisp manual prints in 2 large
volumes, so avoiding any unnecessary bloat there is generally a good
idea).

Thanks.