How to append a newline after every match using xmlint --xpath

Question

I have the following HTML code:

1</script>
<ins class="adsbygoogle"
     style="display:block"
     data-ad-client="ca-pub-5408099190056760"
     data-ad-slot="7305827575"
     data-ad-format="auto"
     data-full-width-responsive="true"></ins>
<script>
     (adsbygoogle = window.adsbygoogle || []).push({});
</script>        </div>
      </div>
      
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                <span>(楼主)</span>
            
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                <span>2021-01-02 01:48</span>
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              <p>          
<p>I did the following, ugly trick, please feel free to provide a better solution.</p>

<p>Changed the HTML code by replacing <code> with \n using the following command:


sed 's/\<\/textarea/\'$'\n\<\\/textarea/g' f