typescript/react-apollo: Generate docblocks for hooks

[CarloPalinckx]

This PR:

• Adds docblock generation to the react-apollo plugin.
• Adds jest-docblock (from their official repo) dependency to parse docblocks in tests.
• A test to cover the new functionality.

Few things I would like to receive some feedback on:

• Should we also be looking into docblocks for HOC and Component API's?
• What exactly would we want to put in the docblocks, since the generated code is only used by typescript/flow users, I wonder how much benefit annotations like typedef have.

resolves #2558

[dotansimha]

That's awesome! Thank you @CarloPalinckx !

[levrik]

Why is this feature not toggleable? We're checking in our generated files and this generated a huge amount of noise. Also we're not seeing any value in that for us.

[n1ru4l]

@levrik Pretty sure a pulll request for this will be accepted! It should be pretty easy too!

[CarloPalinckx]

@levrik @n1ru4l I'll have a look 👍, default behaviour would be to add the comments? I understand that you could see it as noise but I think IDE integrations outweigh clutter in generated files.

[levrik]

@CarloPalinckx Actually for me these docs doesn't add that much value since I know Apollo and the autocompletion provided by the typings is enough. Maybe it could help new team members that don't know the tech stack.

[CarloPalinckx]

@levrik a configuration option was added to disable the docblocks #2717

[levrik]

@CarloPalinckx awesome, thanks.