Add YAML to CSpell languageSettings

Commit 21ef5bd updated VSCode CSpell extension ("code-spell-checker")
settings to refine spell checking for specific file types.

This commit will update `cspell.json` to configure YAML spell checking.
Note that spurious errors will be reported when using some YAML-related
VSCode extensions like vscode-github-actions. This may be due to how
VSCode extensions can define custom language identifiers. In the case of
vscode-github-actions, it overrides the YAML language identifier with a
custom identifier `github-actions-workflow`.

https://code.visualstudio.com/docs/languages/identifiers
https://github.com/github/vscode-github-actions/blob/e335065be26968146ecf63aa1a06e54b6b546839/package.json#L32-L63

vscode/User/cspell.json

@@ -63,6 +63,10 @@
     {
       "languageId": "vue",
       "includeRegExpList": ["(<!--).*(-->)", "CStyleComment"]
+    },
+    {
+      "languageId": "yaml",
+      "includeRegExpList": ["/#.*/"]
     }
   ],
   "words": [