...

$/ = '';
my %list;
while ( my $block = <DATA> ) {
    my ($tag, @list) = split /\n/, $block;
    s/^-- // for @list;
    $list{$tag} = \@list;
}

my $row = 0;
foreach my $tag ( @{ $list{'main'} } ) {
    if ( exists $list{$tag} ) {
        $worksheet->write($row, 0, $tag);
        $worksheet->write_row($row++, 1, $list{$tag});
    }
}

...