Add ability to click through to block-editor package functions on GitHub.

[StevenDufresne]

When you lookup a WordPress function, you can see the underlying source code or click through using the View on Trac or View on GitHub links. This is really useful in understanding how to use the function. Currently, there isn't an easy way to see the source code for Block Editor package functions.

Can we do one of the following:

• Include Block Editor package functions in the code reference ?
• Link the functions in the package readmes (Example)?