RFC: Add generic type to useFlags

[jamiehaywood]

Is your feature request related to a problem? Please describe.
It would be great to get intellisense when destructuring the flags from useFlags

Describe the solution you'd like
To pass a generic to the useFlags hook:

interface Flags {
  featureFlagOne: boolean
}

const { featureFlagOne } = useFlags<Flags>()

[yusinto]

Thank you for requesting this. This makes sense. We'll raise this internally and I'll update this issue when there's one.

[jamiehaywood]

thanks @yusinto - I'm happy to write a PR to support this, just wanted to get validation around the idea.

[yusinto]

@jamiehaywood a PR will be super! Thank you for this.