Add feedback widget to all docs pages and add feedback button to the doc type nav

[anita-trimbur]

Overview

We'd like to raise the prominence of our feedback functionality in tandem with changes to our Docs & Registry. The changes expand the number of selection from 2 (thumbs up or down) to a scale of 4 reactions. It introduces a feedback widget at the bottom of any hand-authored doc. It also provides access to a feedback dialog via the doc type navigation accessible from every page across docs & registry.

Design file

Figma preview

Changes

• [ ] Replaces thumbs up / thumbs down with a scale of 4 reactions
• [ ] Introduces a widget at the bottom of hand-authored docs
• [ ] Moves GitHub links into the widget (with label and icon changes)
• [ ] Adds a "Feedback" button in the Developer navigation
• [ ] Incorporates reactions into the feedback dialog (minor style changes)
• [ ] Ensure new data maps with old data (e.g. "thumbs up" translates into "useful")