title: AMP query_param substitution in anchor tag for AMP HTML pages
body: <p>AMP docs that state I should be able to use QUERY_PARAMS inside my href tag. </p>
  
  <p>My base url is:</p>
  
  <pre><code>http://localhost:3000/lp/test?amp=true?c=hello
  </code></pre>
  
  <p>My anchor tag is as follows:</p>
  
  <pre><code>&lt;a href="http://localhost:3000/lp/test?amp=true?test=QUERY_PARAM(c)"&gt;&lt;/a&gt;
  </code></pre>
  
  <p>With this in mind, I expect <code>QUERY_PARAM(c)</code> to be replaced with <code>hello</code> unless I interpreted the docs incorrectly. However, when I try to inspect the anchor tag on my page, the url comes out exactly as how it was before.</p>
  
  <p>Expectation:</p>
  
  <pre><code>&lt;a href="http://localhost:3000/lp/test?amp=true?test=QUERY_PARAM(c)" data-amp-replace="QUERY_PARAM"&gt;&lt;/a&gt;
  </code></pre>
  
  <p>Actual:</p>
  
  <pre><code>&lt;a href="http://localhost:3000/lp/test?amp=true?test=QUERY_PARAM(c)" data-amp-replace="QUERY_PARAM"&gt;&lt;/a&gt;
  </code></pre>
  
  <p>When I click on the link, the url changes to the following. It seems like it's the not grabbing the query parameter</p>
  
  <pre><code>http://localhost:3000/lp/test?amp=true?test=
  </code></pre>