Fix sphinx warnings and made code block emphasize the relevant line

Signed-off-by: Shay Nehmad <shayn@recolabs.ai>

Author: ShayNehmad-RecoLabs

docs/index.rst

@@ -24,6 +24,7 @@ Contents:
     quick-start
     api
     migrating
+    troubleshooting
 
 
 If you still can't find what you're looking for, try in one of the following pages:

docs/troubleshooting.rst

@@ -13,17 +13,19 @@ It seems like in some situations, installing and then updating ``betterproto`` i
 
 To do that, run ``poetry env info`` to see the venv path:
 
-```sh
-❯ poetry env info
-
-Virtualenv
-Python:         3.8.7
-Implementation: CPython
-Path:           /home/username/.cache/pypoetry/virtualenvs/project-name-random-py3.8  # <-- THIS PATH
-Valid:          True
-```
-
-Then just ``rm -rf`` that path to delete the venv, and re-create the env using `poetry shell` and `poetry install`.
+.. code-block:: shell
+   :linenos:
+   :emphasize-lines: 6
+
+   $ poetry env info
+   
+   Virtualenv
+   Python:         3.8.7
+   Implementation: CPython
+   Path:           /home/username/.cache/pypoetry/virtualenvs/project-name-random-py3.8  # <-- THIS PATH
+   Valid:          True
+
+Then just ``rm -rf`` that path to delete the venv, and re-create the env using ``poetry shell`` and ``poetry install``.
 
 .. _Slack: https://join.slack.com/t/betterproto/shared_invite/zt-f0n0uolx-iN8gBNrkPxtKHTLpG3o1OQ