Pedantic documentation errors.

[Brian Gough]

Toby White writes:
 >  Looking through the example programs given in the documentation, I
 > notice that a large number of them contain an error.
 >  Specifically, they nearly all (with one or two honourable
 > exceptions) have a main() with no return.
 >  I realise this has very little effect on anything, but I thought
 > I'd mention it anyway.

Yes, there are a few other non-ansisms too, like non-constant
initialisers.  I'll try to get them fixed before I publish the manual.