fix sphinx-lint errors in docs and add ci

This change mainly fixes incorrect use of backticks
but also adress some other minor issues like unbalanced
backticks, incorrect spacing or missing _ in links.

This change add a tox target to run sphinx-lint
as well as adding it to the relevent tox envs to enforce
it in ci. pre-commit is leveraged to install and execute
sphinx-lint but it does not reqiure you to install the
hooks locally into your working dir.

Change-Id: Ib97b35c9014bc31876003cef4362c47a8a3a4e0e

tox.ini

@@ -131,6 +131,13 @@ deps =
 commands =
   pre-commit run --all-files --show-diff-on-failure codespell
 
+[testenv:sphinx-lint]
+description =
+  Run sphinx lint checks.
+deps = pre-commit
+commands =
+  pre-commit run --all-files --show-diff-on-failure sphinx-lint
+
 [testenv:fast8]
 description =
   Run style checks on the changes made since HEAD~. For a full run including docs, use 'pep8'