Addon-docs: Add transformSource for jsxDecorator, deprecated onBeforeRender

[phated]

Issue: N/A

What I did

I modified where onBeforeRender was called and threaded the story context into that method. This can help users modify the snippet by pulling data that might be on story parameters or somewhere else in the context.

How to test

• Is this testable with Jest or Chromatic screenshots? Yes, Jest
• Does this need a new example in the kitchen sink apps? I don't this so.
• Does this need an update to the documentation? It isn't mentioned in the docs currently.

If your answer is yes to any of these, please make sure to include it in your PR. ✅

[shilman]

build is failing. are you able to access the circle ci logs?

$ node ../../scripts/prepare.js
src/frameworks/react/jsxDecorator.test.tsx(135,29): error TS7006: Parameter 'dom' implicitly has an 'any' type.

[phated]

I'm not sure what "teamcity" is or why it is failing now. I don't have access to that.

[phated]

Updated the code (and title of this issue) as per discord discussion. 🎉