The portion that needs to be wrapped in a $list
widget is the part that calls the macros – trying to wrap the macros won't end well because pragmas have to be the first thing in their tiddler.
<$list filter="[all[current]links[]] [all[current]backlinks[]] +[first[]]" variable=_>
<!-- begin part that was already there -->
<div class="sib-link-display">
<<linkDisplay "Links" "links[]" "sib-links">>
<<linkDisplay "Backlinks" "backlinks[]" "sib-backlinks">>
</div>
<!-- end part that was already there -->
</$list>