5-arg xref to Top w/o 3rd arg

[Karl Berry]

Texinfo friends,

One small thing that has always bothered me wrt cross-manual xrefs is
the need to figure out the first node in the printed manual when all
that you really want to do is refer to the manual as a whole.  For
example:
  @xref{Top,, Getting Started, info, GNU Info}.

That first printed node doesn't have a conventional name and is subject
to change.  Besides, the output is:
  See Section "Getting Started" in GNU Info.

But what is actually intended is not to see that one section, but the
whole manual:
  See GNU Info.

Thus, my idea is to say that if the first argument is Top
(case-insensitive), the third
argument is not present, and the fifth argument is present, as in:
  @xref{Top,, info, GNU Info}.

the output in TeX is effectively:
  See @cite{GNU Info}

Right now, the output is:
  See Section "Top" in GNU Info.

which is certainly wrong, as the Top node never (or close enough)
appears in the printed output.  So is there a downside?  Wdyt?
The Info output isn't affected since it never uses the third (or fifth)
arg anyway.

I'm not sure if this would affect the non-TeX formats when
xrefautomaticsectiontitle on, but I don't imagine it's any problem to
implement if so :).  Patrice?

Thanks,
karl