Implement #+MACRO

org/testdata/inline.html

@@ -168,6 +168,14 @@ timestamps
 <li>
 <p>
 <code class="verbatim">#+LINK</code> based links: <a href="https://www.example.com/foobar">https://www.example.com/foobar</a>
+</p>
+</li>
+<li>
+<p>
+<code class="verbatim">#+MACROs</code>: <p>
+<h1>yolo</h1>
+</p>
+
 </p>
 </li>
 </ul>

org/testdata/inline.org

@@ -39,3 +39,5 @@
   - <2019-01-06 18:00 +1w>
 - =#+LINK= based links: [[example:foobar]]
   #+LINK: example https://www.example.com/
+- =#+MACROs=: {{{headline(yolo)}}}
+  #+MACRO: headline @@html:<h1>$1</h1>@@

org/testdata/inline.pretty_org

@@ -39,3 +39,5 @@
   - <2019-01-06 Sun 18:00 +1w>
 - =#+LINK= based links: [[example:foobar]]
   #+LINK: example https://www.example.com/
+- =#+MACROs=: {{{headline(yolo)}}}
+  #+MACRO: headline @@html:<h1>$1</h1>@@