Add shortcuts to focus inputs in Things 3 extension

[vimtor]

Description

Add shortcuts to focus inputs in the Things 3 extension. I've mimicked the official shortcuts except for the title and notes sections since they don't have an official one.

Screencast

https://share.cleanshot.com/yzTf35Wm

Checklist

• I read the extension guidelines
• I read the documentation about publishing
• I ran npm run build and tested this distribution build in Raycast
• I checked that files in the assets folder are used by the extension itself
• I checked that assets used by the README are placed outside of the metadata folder

[raycastbot]

Thank you for your contribution! 🎉

🔔 @loris @andreaselia @jfkisafk @thomaslombart @srikirank you might want to have a look.

You can use this guide to learn how to check out the Pull Request locally in order to test it.

You can expect an initial review within five business days.