Issue 6769 - Avoid hardcoding the URL

pages/exceptions/subdocument.tmpl

 title = $subdocument Exception
 template = testcase
 
 {% set testcase_moreinfo = [
   ("Filter Options", "https://adblockplus.org/filters#options"),
 ] %}
 
 <link rel="stylesheet" href="/testcasefiles/subdocumentexception/stylesheet.css">
 
 <section class="site-panel">
   <h2>$subdocument Exception</h2>
   <p>Check that usage of the $subdocument filter option in an exception filter works as expected.</p>
   <p>With the filter(s) displayed below each test case added to ABP (or with the testcase subscription installed and active), the subdocument/frame should not be blocked while the stylesheet should be.</p>
 </section>
 
 <section class="site-panel">
   <h2>Test case</h2>
   <div class="testcase-container">
     <div class="testcase-row">
       <h3>Frame/Subdocument</h3>
       <iframe src="/testcasefiles/subdocumentexception/frame.html"></iframe>
     </div>
     <div class="testcase-row">
       <h3>Stylesheet</h3>
       <div class="testcase-teststylesheet trap">&nbsp;</div>
     </div>
   </div>
   <h3>Filters</h3>
-  <pre>||testpages.adblockplus.org/testcasefiles/subdocumentexception/*</pre>
-  <pre>@@testpages.adblockplus.org/testcasefiles/subdocumentexception/$subdocument</pre>
+  <pre>||{{ site_url|strip_proto }}/testcasefiles/subdocumentexception/*</pre>
+  <pre>@@{{ site_url|strip_proto }}/testcasefiles/subdocumentexception/$subdocument</pre>
 </section>