Warn about invalid node names

[Glenn Morris]

Hi,

The Texinfo manual says:

   Unfortunately, you cannot use periods, commas, colons or parentheses
   within a node name

Yet makeinfo happily accepts such node names with no complaint.

I really can't see why you would not warn about such things by
default. I'm not the first to say this:

http://lists.gnu.org/archive/html/bug-texinfo/2007-12/msg00031.html
http://lists.gnu.org/archive/html/bug-texinfo/2006-12/msg00016.html

Previously, the explanation was given:

    Because in practice most people prefer to live with the invalid
    node names and the slight bogosity in the resulting Info files
    than obfuscate them for the sake of makeinfo :).

Surely these people can live with the warnings, or use --no-warn?

Maybe the brave new world of makeinfo 5 can revisit this?