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

[Warren Block]

> Most obsessive/pedantic/picky PR of the year goes to me, with:
>
> The man page for diff3(1) refers to 'info diff' instead of
> 'info diff3'
>
>
>> How-To-Repeat:
>
> % man diff3
>
> Compare the similarity of the end of this page with the end of the
> 'man diff' page.
>
> Both refer to 'info diff' for more information, but if you compare
> the results of 'info diff' and 'info diff3' you'll clearly see that
> the man page for diff3 should be referencing 'info diff3'.

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.