Project: Finish getting Input ready for RC

[ecraig12345]

Problem

Input is not ready for beta/RC.

Follow-up of #20159, part of #18131

Appetite

1 week

Solution

• Implement primary slot (currently part of Input: implement primary slot #20863)
• Add onChange with standard signature (currently part of Input: implement primary slot #20863)
• Add docs (text) and stories Input: add stories and restrict type prop #21072
• Run manual accessibility test pass -- tracked by Input a11y pass #21174
• Export Input from react-components (possibly under unstable) Publish react-input and add to react-components under unstable #21142
  • Remove Input from PR deploy site
• Write initial migration guide

Risks (Rabbit holes)

• Getting hung up on discussion on small remaining decisions
• Unable to get reviews due to OOF (mitigation: try to finish ASAP before people leave)

Out of scope (No-gos)