Support inference extra props from as props

[gtkatakura]

What is the purpose of this pull request?

Add support to merge props from the component passed in prop as.

What problem is this solving?

Correct type detection of new props when as is passed.

How should this be manually tested?

The examples of Button.stories.tsx could have correct type.

1. The example Checkbox has changed to compose Button with a and Link, instead compose Checkbox with Button, so the props of a and Link must be merged with the Button in this cases.
2. The examples without defining as should merge the props of ThemeAwareButton by default.

Screenshots or example usage

Before:

After:

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Quality improvement (tests or refactors)
• Breaking change (fix or feature that would cause existing functionality to change)
• Trivial change (small fix or feature that doesn't impact functionalities)
• Requires change to documentation, which has been updated accordingly

How does this PR make you feel? 🔗

Notes

I need to cast the return of forwardRef, because forwardRef don't pass the generics forward.

[gtkatakura]

I don't know if the correct is devDependencies or peerDependencies, because I only use the types of reakit-utils here