Texinfo macros without arguments

[Neil Puttock]

Hi everybody,

Recently I've been getting loads of error messages when building the
docs; they all relate to Texinfo macros which don't have arguments.
Here's a random example:

out-www//notation/repeats.texi:879: warning: @snippets defined with 0
arguments should be invoked with {}

I had a look at the Texinfo documentation, and it says such macros
should always include the braces when invoked, so should we change all
these invocations accordingly?

Regards,
Neil