contrib/wix/defines.wxi

hgweb: clearly outline <tr> block in gitweb and spartan styles

It's easy to miss the closing </tr> tag when it's not on its own line. Some
neighboring blocks also already use this clearer style.

(In 03f692eee31d I didn't even think grepping for this, but this patch should
now cover every occurrence).

<Include>

  <?if $(var.Platform) = "x64" ?>
    <?define IsX64 = yes ?>
  <?else?>
    <?define IsX64 = no ?>
  <?endif?>

</Include>