Fix past-tense "exempt" typo

Co-authored-by: wookie184 <[email protected]>

Author: Bluenix2

pydis_site/templates/events/pages/code-jams/9/rules.html

@@ -19,7 +19,7 @@
             For example, serving static files for a website cannot be done over WebSockets and it does not pose as a significant portion of a project.
         </p>
 
-        <p>This rule does not apply to databases and files when used for <i>storage purposes</i> even though that may be a significant portion of your project. Working with subprocesses (through stdin/stdout or <code>multiprocessing.Pool()</code>/<code>concurrent.futures.ProcessPoolExecutor()</code>) is also exempted of this rule.</p>
+        <p>This rule does not apply to databases and files when used for <i>storage purposes</i> even though that may be a significant portion of your project. Working with subprocesses (through stdin/stdout or <code>multiprocessing.Pool()</code>/<code>concurrent.futures.ProcessPoolExecutor()</code>) is also exempt from this rule.</p>
 
         <p>Reach out to the Events Team for advice if you're about your use of non-WebSocket communication.</p>
     </li>