OpenSystemsDevelopment / qpdf

doc: fix whitespace and indentation in pandoc output

Pandoc indented lists with two spaces after the dash, which is ugly
and messes up emacs fill-paragraph. I transformed the spacing using a
combination of this perl script and manual edits. I verified that the
HTML generated by sphinx was identical before and after the edits and
that this commit contains only whitespace changes. The perl script as
it stands does not do indentation quite right for variable lists, but
there were only about 8 cases that it missed, so I just fixed them
manually.

```perl
#!/usr/bin/env perl
require 5.008;
use warnings;
use strict;
use File::Basename;

my $whoami = basename($0);

my @liststack = ();

while (<>)
{
    if (m/^( *-  )\S/)
    {
        my $pre = $1;
        while ((scalar(@liststack) > 0) &&
               ($liststack[-1] >= length($pre)))
        {
            pop(@liststack);
        }
        if ((scalar(@liststack) == 0) && ($pre =~ m/^ /))
        {
            push(@liststack, 1);
        }
        push(@liststack, length($pre));
        my $n = scalar(@liststack);
        #print "** $n\n";
        my $newpre = ('  ' x ($n - 1)) . '- ';
        s/^$pre/$newpre/;
    }
    elsif (scalar(@liststack) > 0)
    {
        if ($_ ne "\n")
        {
            while (scalar(@liststack) > 0)
            {
                my $pre = m/^( *)/;
                if (length($1) < $liststack[-1])
                {
                    #print "XXX pop\n";
                    pop(@liststack);
                }
                else
                {
                    last;
                }
            }
            my $n = scalar(@liststack);
            #print "** $n\n";
            my $indent = '  ' x $n;
            s/^ +/$indent/;
        }
    }
    print;
}
```