SubscriptionField does not support type builder api access

[jasonkuhrt]

E.g. for queryField:

You can also use it with a function as the first argument, which will pass the t provided to the definition block, especially useful when using with the connection plugin:

export const usersQueryField = queryField(t => {
  t.connectionField('users', {
    type: SomeType,
    resolve() {
      // ...
    },
  })
})

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This does not work for subscriptionField.