Set code type on readme.md examples

[ppicom]

Set the type of code in the examples to Javascript so that readme.md is rendered with fully colored examples.

Pull Request Template

PR Checklist

• I have run npm test locally and all tests are passing.
• I have added/updated tests for any new behavior.
• If this is a significant change, an issue has already been created where the problem / solution was discussed: [N/A, or add link to issue here]

PR Description

I wanted the examples to be more readable, so I added the markdown annotations needed by the markdown editor to render the code in the examples with colors instead of all-white.