bug#70601: join(1) info page -o: too hazy at first

[Dan Jacobson]

The join main page is really clear,

       -o FORMAT
              obey FORMAT while constructing output line

A base hit on the first pitch. The info page on the other hand,

‘-o FIELD-LIST’
‘-o auto’
     If the keyword ‘auto’ is specified, infer the output format from
     the first line in each file.  This is the same as the default
     output format but also ensures the same number of fields are output
     for each line.  Missing fields are replaced with the ‘-e’ option
     and extra fields are discarded.

even after reading down to here, hasn't tipped the user off that it is
talking about the output format! It's its turn up to bat but it's still
drinking coffee in the bullpen.

In fact FIELD-LIST vs FORMAT make the user double check that they are
actually looking at the same commands' documentation.