Automatically Catch Sphinx Errors (#8530)

* clean up some Sphinx warnings

* first attempt at a doc-test pipeline job

* fix formatting

* fix test name

* set env for bash

* try bash vs script

* maybe it didn't like me setting 'PATH'...derp

* drop use of venv

* sphinx-build isn't a py script

* try activating venv

* docs: remove unused html_static tags

* clean up final sphinx build errors for certbot

* clean up final sphinx build errors for acme

* better names for docs pipeline

* fix spelling

* add docs_extras to setup.py

* remove temp doc-testing pipeline; add template to main.yml

* rearrange pipeline execution; run sphinx builds in one job

* add documentation note to compat.os

* add uninstall.rst as a sub-toctree to avoid build error

certbot/docs/conf.py

@@ -95,7 +95,12 @@ language = None
 
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
-exclude_patterns = ['_build']
+exclude_patterns = [
+    '_build',
+    'man',
+    'challenges.rst',
+    'ciphers.rst'
+]
 
 # The reST default role (used for this markup: `text`) to use for all
 # documents.