chore: Update cspell and fix issues

- covert `cSpell.json` to `cspell.config.yaml`
- break up the word list into multiple dictionary files
- fix spelling issues
- Enable spell checking code for non-test files

docs/config/usage.md

@@ -436,3 +436,8 @@ mermaid_config.startOnLoad = true;
 
 > **Warning**
 > This way of setting the configuration is deprecated. Instead the preferred way is to use the initialize method. This functionality is only kept for backwards compatibility.
+
+<!---
+cspell:locale en,en-gb
+cspell:ignore pumbaa
+--->