[antlr-interest] RFE: warn if root rule is missing (no EOF)

[Guntis Ozols]

> This is not a valid thing to do.
> Not everyone WANTs a rule to end in EOF.
>
> Jim

Of course this is not a valid thing to do if you want to
boost trafic for this list, keep newbies puzzled and
everyone else on this list busy.

I am subscribed to this list only for few months,
and seen this EOF issue (and other issues)
pop up numerous times.

To keep everyone happy, there could be command line option
'help-dummies', which could enable this and other warnings.
Hopefully it can be 'on' by default.

Guntis