Update seizures-and-physical-reactions.html (#4361)

closes #4328

changes wcag 2.0 to just wcag 2

removes list of a single bullet: 'Ensuring that content does not violate
spatial pattern thresholds (future link)' that was not created.

Co-authored-by: Patrick H. Lauke <redux@splintered.co.uk>
Co-authored-by: Mike Gower <mikegower@gmail.com>

Author: 3 people

understanding/21/seizures-and-physical-reactions.html

@@ -20,27 +20,11 @@ <h2>Intent of Seizures</h2>
 
 
       <p>The objective of this guideline is to ensure that content that is marked as conforming
-         to WCAG 2.0 avoids the types of flash that are most likely to cause seizure when viewed
+         to WCAG 2 avoids the types of flash that are most likely to cause seizure when viewed
          even for a second or two.
       </p>
 
    </section>
 
-   <section id="advisory">
-      <h3>Additional Techniques (Advisory) for Seizures</h3>
-      
-      
-      <ul>
-         
-         <li>
-            Ensuring that content does not violate spatial pattern thresholds (future link)
-            
-         </li>
-         
-      </ul>
-      
-   </section>
-   
-   
-   
-</body></html>
+
+</body></html>