title: htmlagilitypack select <a> tag with specified inner text
body: <p>i need to select a tag that contains an innertext i specify.
  can anyone help me with the xpath query ie <code>&lt;a href="#"&gt;wake up&lt;/a&gt;</code>. So if i pass wake to the xpath, it should select this a link</p>
  
  <p>thanks</p>