Add contributing instructions to PULL_REQUEST_TEMPLATE

[wesleyboar]

Issue: An ignorant new contributor may not see the "Helpful resources" links (example: #17703).

What I did

Add helpful link about contribution to the PR description. (This may help new contributors who only read the template.)

What I thought about doing…

• I thought about writing For additional guidance, see https://github.com/storybookjs/storybook/blob/next/CONTRIBUTING.md, but then there's the weird period-after-a-link legibility and usability issue.
• I also used the word "guidance" instead of "direction" so as to suggest more that the contributor has a choice (because everyone is sensitive nowadays).

How to test

Might not be testable.

Change is in a PR template, so I don't think it is usable without being in master.
Change is in a comment, so it will not render in a preview of the document.

• Is this testable with Jest or Chromatic screenshots?
• Does this need a new example in the kitchen sink apps?
• Does this need an update to the documentation?

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

[nx-cloud]

☁️ Nx Cloud Report

CI ran the following commands for commit 3470b0e. Click to see the status, the terminal output, and the build insights.

📂 See all runs for this branch

---

✅ Successfully ran 1 target

• nx run-many --target=prepare --all --parallel --max-parallel=15 -- --optimized

---

Sent with 💌 from NxCloud.

[wesleyboar]

Closes #17703

[shilman]

Great idea @tacc-wbomar!! But what do you think about linking directly to the updated guide here? https://storybook.js.org/docs/react/contribute/how-to-contribute

[wesleyboar]

@shilman, Thanks for looking. I've made that change. I do have reservations.

• The website document URL has react in it, but is not limited to react. Were I a careful reader, and contributing to not-react code, I might think that is the wrong document for me.
• Will the CONTRIBUTING.md doc become useful? It mentions transition but perhaps that means it will be deprecated not improved.

[yannbf]

Hey @tacc-wbomar thank you so much for your contribution!

The website document URL has react in it, but is not limited to react. Were I a careful reader, and contributing to not-react code, I might think that is the wrong document for me.

This is just how our documentation website works, given that docs have to be based on a framework. That could be any framework, it will result in the same contribution page regardless.

Will the CONTRIBUTING.md doc become useful? It mentions transition but perhaps that means it will be deprecated not improved.

I believe it will just point people to the website