[latexrefman] Make all pages in the documents after this declaration have the same

[Karl Berry]

    https://svn.gnu.org.ua/viewvc/latexrefman/trunk/latex2e.texi?r1=1083&r2=1082&pathrev=1083

Thanks. As far as I can see, my change is correct. In the classes.dtx
LaTeX source file, I see:

    \if at twocolumn
      \twocolumn
      \sloppy
      \flushbottom

Which is clearly about [twocolumn], not [twoside].

I also added the note about {makeidx} because
of another call to \flushbottom in makeindx.dtx. Those are the only two
places \flushbottom is called in LaTeX's *.dtx, from a simple grep.

If you think it should be otherwise, please reference the LaTeX sources
that say so, and/or an actual test document showing the results. 

I generally make changes like this after detailed searching of the LaTeX
sources. (This is supposed to be a reference manual, after all, so I try
to go to the real reference: the sources.) I don't have time to redo all
my research every time you question a change.  Please, if you think what
I wrote is wrong, don't just hypothesize about it or ask me to back up
my change. Instead, find the counter-evidence that my change is wrong. I
make plenty of mistakes, and LaTeX is so complicated that it's hard to
be sure of anything, but I try not to do carelessly. --best, karl.