Improve the contributing guide

Author: greyli

CONTRIBUTING.rst

@@ -12,14 +12,16 @@ to address bugs and feature requests in Flask itself. Use one of the
 following resources for questions about using Flask or issues with your
 own code:
 
--   The ``#get-help`` channel on our Discord chat:
+-   The ``#questions`` channel on our Discord chat:
     https://discord.gg/pallets
 -   The mailing list [email protected] for long term discussion or larger
     issues.
 -   Ask on `Stack Overflow`_. Search with Google first using:
     ``site:stackoverflow.com flask {search term, exception message, etc.}``
+-   Ask on our `GitHub Discussions`_.
 
 .. _Stack Overflow: https://stackoverflow.com/questions/tagged/flask?tab=Frequent
+.. _GitHub Discussions: https://github.com/pallets/flask/discussions
 
 
 Reporting issues
@@ -92,7 +94,7 @@ First time setup
 
     .. code-block:: text
 
-        git remote add fork https://github.com/{username}/flask
+        $ git remote add fork https://github.com/{username}/flask
 
 -   Create a virtualenv.