Hi emacs developers.

In maintaining.texi:2472,there is a @code{DEL} Texinfo markup.

I am trying to translate emacs-26 manuals,
and there are many fixes @code{key} to @{Key} or @kbd{@key{Key}}.

So,I think this should also be fixed to either

Thanks.

ayatakesi <ayanokoji.takesi@gmail.com>