Docs: Recommend forum for model-related questions.

docs/manual/introduction/Loading-3D-models.html

@@ -117,16 +117,13 @@
   <p>
     If you've gone through the troubleshooting process above and your model
     still isn't working, the right approach to asking for help will get you to
-    a solution faster. Whenever possible, include your model (or a simpler
-    model with the same problem) in any formats you have available. Include
-    enough information for someone else to reproduce the issue quickly —
-    ideally, a live demo.
+    a solution faster. Post a question on the
+    [three.js forum](https://discourse.threejs.org/) and, whenever possible,
+    include your model (or a simpler model with the same problem) in any formats
+    you have available. Include enough information for someone else to reproduce
+    the issue quickly — ideally, a live demo.
   </p>
 
-  <p>
-    TODO: Do we recommend model-related questions go to GitHub, Stack Overflow,
-    or the Discourse forum?
-  </p>
 </body>
 
-</html>
+</html>