docs/184791: [patch] man page for 'diff3' references 'info diff' instead of 'info diff3'

[Jamie Landeg Jones]

> Agreed.  However, this is "contrib" software from an external source, 
> and we generally prefer to get them patched upstream to avoid having to 
> maintain local patches.  I think this is the project page:
> http://www.gnu.org/software/diffutils/
>
> It's not clear how they prefer to get bug reports, but maybe a post to 
> their mailing list would help.

Ahhhh. Yeah. That makes sense. I'll persue that avenue. Sorry for the
unintentional 'spam'. Feel free to close the PR!

Cheers for the reply, Jamie