breaking(Popup): rename positioning to position

[levithomason]

Many components currently accept a position prop. The Popup, however, calls this prop positioning. We should update the Popup prop positioning to be position.

This new prop name needs to be updated in:

• the component
• tests
• doc site usages

Since the old prop will no longer work, this will be a breaking change and ship with the next minor bump of the library (since we are pre 1.0).

[tarang9211]

@levithomason I'll pick this up.

[tarang9211]

@levithomason I thought I was picking this one up?

[levithomason]

I'd take this up with @kamdz. I have no control over who does what since it is open source. Perhaps open your PR immediately after you begin work on the issue, as well as leave a comment.

That said, all PRs are gladly accepted from anyone who submits them :) I surely don't want to hinder folks from contributing.

[levithomason]

Merged in #1342