fixed 'Private Search Engines' header

- signed-off-by: trimstray <trimstray@gmail.com>

README.md

@@ -422,7 +422,7 @@ performance of any of your sites from across the globe.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://www.ostorlab.co/scan/mobile/"><b>Ostorlab</b></a> - analyzes mobile application to identify vulnerabilities and potential weaknesses.<br>
 </p>
 
-###### :black_small_square: Private Search Engines
+##### :black_small_square: Private Search Engines
 
 <p>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://www.startpage.com/"><b>Startpage</b></a> - the world's most private search engine.<br>