[vale] Add some vale styles and an ini file

vale/.vale-styles/Microsoft/HeadingAcronyms.yml

@@ -0,0 +1,7 @@
+extends: existence
+message: "Avoid using acronyms in a title or heading."
+link: https://docs.microsoft.com/en-us/style-guide/acronyms#be-careful-with-acronyms-in-titles-and-headings
+level: warning
+scope: heading
+tokens:
+  - '[A-Z]{2,4}'