Improved user guide, added CI vale for docs (#2308)

* restructured user guide, minor fixes

* added index file for user guide

* github actions for vale

* testing workflow

* CI vale

* changes as per vale's suggestions

* set CI vale on pull request

* adding homebrew script to macos infra setup file

* fix CI errors

* testing vale

* testing vale

* testing vale

* testing vale

* testing vale

* testing vale

* testing vale

* testing vale

* testing vale

* testing vale

* testing vale

* testing vale

* testing vale

* testing vale

* testing vale

* testing vale

* testing vale

* testing vale

* vale testing complete

* vale cleanup

* vale test

* vale test for github-pr-check

* vale test for github-pr-check

* vale test for github-pr-check

* vale test for github-pr-check

* testing vale warnings

* testing vale warnings

* testing vale warnings

* testing vale warnings

* testing vale warnings

* testing vale warnings

* testing vale warnings

* swizzled doc cards to add icons

* Align CI params to other CIs

---------

Co-authored-by: Félix Malfait <felix.malfait@gmail.com>

.github/styles/write-good/meta.json

@@ -0,0 +1,4 @@
+{
+  "feed": "https://github.com/errata-ai/write-good/releases.atom",
+  "vale_version": ">=1.0.0"
+}