Add ability for readers to indicate whether a docs page was helpful, and give feedback in-place

[jmagman]

Describe the problem

It would be great to get feedback about particular doc pages, which would help us prioritize docs that are getting negative feedback.

For example

1. Firebase docs: at the bottom are "Was this helpful?" thumbs-up thumbs-down buttons, and a "Send feedback" button .

The "Send feedback" button opens a form:

However, we could just redirect to https://github.com/flutter/website/issues/new/choose

2. expo has something similar

Expected fix

Add ability for readers to indicate whether a docs page was helpful, and give feedback in-place.

On which browser(s) did you experience this issue?

No response

Additional context

No response

I would like to fix this problem.

• [ ] I will try and fix this problem on docs.flutter.dev.

[sfshaza2]

Yes, this would be helpful.