Add the WebNN code example

[huningxin]

Add a live example based on the code example in WebNN spec

[huningxin]

I am working on something like the following screenshot:

It is inspired by the code snippet of tf.js API doc, e.g. tf.add.

The code editor shows the sample code. The users can click the "Run" button to execute the code and see the output in the "console log". The users can click the "Edit" button to modify the code, e.g. change the input value, and run the modified code.

@anssiko @pyu10055 and @wchao1115 any thoughts?

[anssiko]

I'm a fan of this feature, and it would surely help lower the threshold for experimentation by web developers. Maybe we should consider adding a feedback mechanism as well in the API docs (e.g. simply add a link to open a new issue in the webnn-polyfill repo) to capture web developer feedback early. I suspect API docs is much more familiar interface to learn about the API than the web spec repo for web developers, and we might capture more such feedback that way. Feel free to open a separate issue to track that proposal.

[huningxin]

I'm a fan of this feature, and it would surely help lower the threshold for experimentation by web developers.

Thanks. I'll open a PR for review.

Feel free to open a separate issue to track that proposal.

done. webmachinelearning/webnn-polyfill#21