adapted accessible footnotes test to add role=doc-noteref - it looks …

…like Kramdown's output required the test to include role=doc-noteref to validate accessible HTML

spec/requests/accessible_footnotes_spec.rb

@@ -8,8 +8,8 @@
   subject { response.body }
 
   it "makes footnotes accessible" do
-    is_expected.to include(%(<a href="#fn:1" class="footnote" rel="footnote"><span class="visually-hidden">Footnote </span>1</a>))
-    is_expected.to include(%(<a href="#fn:2" class="footnote" rel="footnote"><span class="visually-hidden">Footnote </span>2</a>))
+    is_expected.to include(%(<a href="#fn:1" class="footnote" rel="footnote" role="doc-noteref"><span class="visually-hidden">Footnote </span>1</a>))
+    is_expected.to include(%(<a href="#fn:2" class="footnote" rel="footnote" role="doc-noteref"><span class="visually-hidden">Footnote </span>2</a>))
 
     is_expected.to include(%(<a href="#fnref:1" class="reversefootnote" role="doc-backlink"><span class="visually-hidden">Location of footnote 1</span>↩</a>))
     is_expected.to include(%(<a href="#fnref:2" class="reversefootnote" role="doc-backlink"><span class="visually-hidden">Location of footnote 2</span>↩</a>))