Add lossless inline-definition-footnote rendering for the OrgWriter

org/testdata/example.html

@@ -65,7 +65,7 @@
 <ul>
 <li>normal footnote reference <sup class="footnote-reference"><a href="#footnote-1">1</a></sup></li>
 <li>further references to the same footnote should not <sup class="footnote-reference"><a href="#footnote-1">1</a></sup> render duplicates in the footnote list</li>
-<li>also inline footnotes are supported via <code class="verbatim">fn:2:inline definition</code>. But we won&#39;t test that because it would cause the output to look different from the input </li>
+<li>inline footnotes are also supported via <sup class="footnote-reference"><a href="#footnote-2">2</a></sup>. </li>
 </ul>
 <div id="footnotes">
 <h1 class="footnotes-title">Footnotes</h1>
@@ -74,5 +74,8 @@
 <sup id="footnote-1">1</sup>
 <p>Foobar</p>
 </div>
+<div class="footnote-definition">
+<sup id="footnote-2">2</sup>
+the inline footnote definition</div>
 </div>
 </div>

org/testdata/example.org

@@ -53,8 +53,7 @@ this one is cheating a little as tags are ALWAYS printed right aligned to a give
 ** Footnotes
 - normal footnote reference [fn:1]
 - further references to the same footnote should not [fn:1] render duplicates in the footnote list
-- also inline footnotes are supported via =fn:2:inline definition=. But we won't test that because it would
-  cause the output to look different from the input
+- inline footnotes are also supported via [fn:2:the inline footnote definition].
 
 * Footnotes
 [fn:1] Foobar