Fix various reference issues in documentation

Co-Authored-By: Riley Shaw <30989490+ShineyDev@users.noreply.github.com>

docs/quickstart.rst

@@ -56,7 +56,7 @@ There's a lot going on here, so let's walk you through it step by step.
    is the same as the :attr:`Client.user`.
 5. Afterwards, we check if the :class:`Message.content` starts with ``'$hello'``. If it does,
    then we send a message in the channel it was used in with ``'Hello!'``. This is a basic way of 
-   handling commands, which can be later automated with the :ref:`ext.commands` framework.
+   handling commands, which can be later automated with the :doc:`./ext/commands/index` framework.
 6. Finally, we run the bot with our login token. If you need help getting your token or creating a bot,
    look in the :ref:`discord-intro` section.