docs: add an explanation for excludeVerboseContent

[lulzneko]

Objective

Add a description of the excludeVerboseContent option to the documentation.

Detail

• Clarified the default value of the excludeVerboseContent option.
• Added supplementary information because CFn setting values and AppSync settings have opposite meanings.

[lulzneko]

This pull request is only for documentation changes and has nothing to do with errors in CI.

The Lint error in CI is resolved by the pull request in #440.

After the Lint error is resolved, the next error is the Test error.
Test error, which will be resolved in the #441 pull request.

[bboure]

LGTM, thanks @lulzneko
plus just don't commit yarn-error.log (let's add it to .gitignore

[lulzneko]

@bboure
yarn-error.log was an unnecessary commit. Sorry about that.
I have removed yarn-error.log from the pull request.

[bboure]

Thank you!