Consider adding JSDoc-style comments to the examples

[jschlight]

This issue on the node-addon-api repository raises the question of using JSDoc-style comments in C++ code implementing native addons:

https://github.com/nodejs/node-addon-api/issues/758

In addition, @mhdawson has identified another potential benefit of adding JSDoc-style comments to the C++ code:

https://github.com/nodejs/node-addon-api/pull/749#issuecomment-656361110

Once the tutorial site lands, I'd like to do a review of the current content and at that time I can investigate the feasibility of adding JSDoc-style comments to our examples.

[mhdawson]

As discussed in the N-API team meeting today, sounds like a great idea.