Correct link in pause-stop-hide.html (#4456)

While responding to #4447 I noticed
that the url to [2.3.3 Animation from
Interaction](https://www.w3.org/WAI/WCAG21/Understanding/animation=from=interaction)
in a note is broken since it contains equal signs instead of hyphens
No idea how long this has been here. Replacing equal signs with dashes
so that the link works.

Author: mbgower

understanding/20/pause-stop-hide.html

@@ -95,7 +95,7 @@ <h2>Intent of Pause, Stop, Hide</h2>
          <p>Moving, blinking, scrolling content that starts automatically because of a general user interaction (such as focusing/hovering over an element,
             or scrolling the page), rather than as a result of an intentional <em>activation</em> (such as activating a button),
             and which doesn't provide provide a way to Pause, Stop, or Hide, will fail this Criterion, and potentially
-            <a href="animation=from=interaction">2.3.3 Animation from Interaction</a>.</p>
+            <a href="animation-from-interaction">2.3.3 Animation from Interaction</a>.</p>
       </div>
 
       <p>It is important to note that the terms "blinking" and "flashing" can sometimes refer to the same content.</p>