Vale: Add US spelling test

Signed-off-by: Lynette Miles <[email protected]>

Author: esmerel

CONTRIBUTING.md

@@ -128,6 +128,7 @@ at the `suggestion` level and won't block merging.
 
 The following tests are at a `error` level and will prevent merging:
 
+- [AmSpelling](https://developers.google.com/style/word-list)
 - [NonStandardQuotes](https://github.com/fluent/fluent-bit-docs/blob/master/vale-styles/FluentBit/NonStandardQuotes.yml):
   [Use standard quotes](https://developers.google.com/style/quotation-marks#straight-and-curly-quotation-marks).
   By default, Google Docs and Microsoft Word turn standard straight quotes into "smart"

vale-styles/FluentBit/AmSpelling.yml

@@ -1,8 +1,8 @@
 extends: existence
-message: "In general, use American spelling instead of '%s'."
+message: "In general, use US English spelling instead of '%s'."
 link: 'https://developers.google.com/style/spelling'
 ignorecase: true
-level: suggestion
+level: error
 tokens:
   - '(?:\w+)nised?'
-  - '(?:\w+)logue'
+  - '(?:\w+)logue'