chore: stop ignoring auto-generated docs

It makes sense to track these docs in git in my opinion. That way, we
can add an action to check docs are updated before merging, similar to
how we check generated mocks.

Including the docs in github could also serve as a valuable reference
location alongside RTD.

Author: jack-w-shaw

docs/.gitignore

@@ -1,7 +1,3 @@
-user/reference/juju-cli/list-of-juju-cli-commands/*
-user/reference/configuration/list-of-controller-configuration-keys.md
-user/reference/configuration/list-of-model-configuration-keys.md
-
 # Starter pack rules start here
 /*env*/
 .sphinx/venv/
@@ -17,4 +13,4 @@ __pycache__
 .vscode/
 .sphinx/styles/*
 .sphinx/vale.ini
-sp-docs/_build
+sp-docs/_build