Enable vale for prose linting (#3)

* Enable vale in CI

* Add vale config

* Tweak vale

* Update config

* Update .gitignore

* Switch back

* Rename CI

* Add badges

* Tidy up CI

* Change image

* Configure vale

* Delint

* Update README

.github/styles/Google/Headings.yml

@@ -0,0 +1,29 @@
+extends: capitalization
+message: "'%s' should use sentence-style capitalization."
+link: "https://developers.google.com/style/capitalization#capitalization-in-titles-and-headings"
+level: warning
+scope: heading
+match: $sentence
+indicators:
+  - ":"
+exceptions:
+  - Azure
+  - CLI
+  - Cosmos
+  - Docker
+  - Emmet
+  - gRPC
+  - I
+  - Kubernetes
+  - Linux
+  - macOS
+  - Marketplace
+  - MongoDB
+  - REPL
+  - Studio
+  - TypeScript
+  - URLs
+  - Visual
+  - VS
+  - Windows
+  - JSON