Update README with Github discussion link (#2419)

* Update README with Github discussion link

* Changed the wording to give more context

* Changed formatting to make it more readable

* Finalized wording

README.md

@@ -18,8 +18,12 @@ imperfect gate applications, state preparation and measurement errors, etc.
 Error mitigation seeks to reduce these effects at the software level by
 compiling quantum programs in clever ways.
 
-Want to know more? Check out our
-[documentation](https://mitiq.readthedocs.io/en/stable/guide/guide.html), chat with us on [Discord](http://discord.unitary.fund), and join our weekly community call ([public agenda](https://docs.google.com/document/d/1lZfct4AOCS7fdyWkudcGyER0n0nsCxSFKSicUEeJgtA/)).
+Want to know more? 
+- Check out our
+[documentation](https://mitiq.readthedocs.io/en/stable/guide/guide.html).
+- For code, repo, or theory questions, especially those requiring more detailed responses, submit a [Discussion](https://github.com/unitaryfund/mitiq/discussions).
+- For casual or time sensitive questions, chat with us on [Discord](http://discord.unitary.fund).
+- Join our weekly community call on [Discord](http://discord.unitary.fund) ([public agenda](https://docs.google.com/document/d/1lZfct4AOCS7fdyWkudcGyER0n0nsCxSFKSicUEeJgtA/)).
 
 ## Quickstart