Implement arrow interactions as arrowPress

[juanca]

What: Add arrow interactions to the user-event API

Why: Arrow interactions emit key down event, maybe a key press event (I need help on this), and a key up event -- in that particular order. Arrow interactions are crucial in implementing accessibility support for UI widgets. However, there are more than just arrows -- we also need a HOME and END (to name a couple) keys support.

How: Adds an arrowPress function to the module API -- however, perhaps it makes more sense to expose these interactions as a different API (and for better long-term purposes)

Checklist:

• Documentation
• Tests
• Typings
• Ready to be merged
  

This is not ready to be merged. As I developed this, I figured I should get more feedback on the API design and testing design. I can follow up on documentation and typing -- though, I will be honest, I don't know how typing are defined in this repository -- and any additional PR checklist/revisions/what-have-yous.

Thank you for your time!

[codecov]

Codecov Report

Merging #300 into master will increase coverage by 0.02%.
The diff coverage is 92.30%.

@@            Coverage Diff             @@
##           master     #300      +/-   ##
==========================================
+ Coverage   98.90%   98.92%   +0.02%     
==========================================
  Files           1        1              
  Lines         182      186       +4     
  Branches       56       56              
==========================================
+ Hits          180      184       +4     
  Misses          2        2              

Impacted Files	Coverage Δ
src/index.js	98.92% <92.30%> (+0.02%)	⬆️

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[juanca]

Uh, looks like my IDE removed a bunch of things. 🤔 I didn't see those changes in git add --patch.

EDIT: I would still appreciate some feedback.

[juanca]

Note for future self:

• Implement generic keydown -- we want to use Home and End keys too! Custom shortcuts should be supported
• Always fire event on the document.activeElement. That is how a user would interact with a UI.

[nickmccurdy]

This seems similar to #354, what do you think about it? I started writing tests but you can help out with the implementation if you'd like.

[juanca]

I'm open to collaborating. Let me know the repo#branch combo and I can start digging later today / tomorrow as I balance some work priorities with downtime.

[nickmccurdy]

Sorry I got distracted and my test doesn't really have any useful assertions (just a snapshot that's currently incorrect), but here's what I started with as an example:

test('{right} on a radio button', () => {
  const {element: button, getEventCalls} = setup(
    <>
      <input type="radio" name="example" defaultChecked />
      <input type="radio" name="example" />
      <input type="radio" name="example" />
    </>,
  )

  userEvent.type(button, '{right}')
})

After this only the second radio should be checked.

[juanca]

I ended up going a different route: using the event snapshot. See #371

Feedback on the PR would be appreciated. Let me know if this is aligned with your thoughts on the user-event API -- I may have done one too many assumptions.