getting_help.topic: Mention "Discourse" explicitly

Author: karollewandowski

topics/intro/getting_help.topic

@@ -39,7 +39,7 @@
         </tip>
         <p>For questions, problems, or other discussions about plugin development itself
             (rather than the content of this guide),
-            use our <a href="https://platform.jetbrains.com">JetBrains Platform</a> community forum.
+            use our <a href="https://platform.jetbrains.com">JetBrains Platform</a> community Discourse forum.
             The forum is monitored by JetBrains team members.</p>
         <p>Of course, all raised questions will be used to try and improve this guide.</p>
     </chapter>