[FIXED JENKINS-14434] 96442cd9 broke "Delete" buttons in some cases.

Seems to be due to hetero-list.jelly importing repeatableDeleteButton.jelly but nothing on the page loads repeatable.js.
(Presumably worked for /configure just by accident because someone else included repeatable.jelly on the same page.)

core/src/main/resources/lib/form/repeatableDeleteButton.jelly

@@ -31,5 +31,6 @@ THE SOFTWARE.
       Caption of the button. Defaults to 'Delete'.
     </st:attribute>
   </st:documentation>
+  <st:adjunct includes="lib.form.repeatable.repeatable"/>
   <input type="button" value="${attrs.value ?: '%Delete'}" class="repeatable-delete" />
 </j:jelly>
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