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

.cspell/contributors.txt

@@ -0,0 +1,8 @@
+# Contributors to mermaidjs, one per line
+cpettitt
+Dong Cai
+Nikolay Rozhkov
+Peng Xiao
+subhash-halder
+Vinod Sidharth
+Ashish Jain