Add "<br><br>" after every 5 sentences?
<p>Imagine a very long article with no line breaks. It's just like</p>

<pre><code>sentence 1. sentence 2. sentence 3. sentence 4. sentence 5. sentence 6. sentence 7. 
sentence 8. sentence 9. sentence 10. sentence 11. sentence 12. sentence 13. sentence 14. 
sentence 15. sentence 16. sentence 17. sentence 18. sentence 19. sentence 20. sentence 
21. sentence 22. sentence 23. sentence 24. sentence 25.
</code></pre>

<p>I want to add line breaks after every 5 sentences. Or after every 5th ". "</p>

<p>How can I do that ?</p>
