Fix the incorrect type annotation for ref in JSX4

[mununki]

Fixes #6714

In the Discouraged ForwardRef use case, if ref did not have a type annotation, JSX4 added an incorrect type as an annotation during transformation. While this PR change may cause build errors where the type 'ref cannot be generalized, I don't think it will be a problem because in most cases the type of ref can be inferred from the ForwardRef component implementation. I think adding an incorrect type is a bigger problem.

Original

module ForwardRef = {
  @react.component
  let make = React.forwardRef(ref => {
    React.useImperativeHandle1(
      ref,
      () =>
        Js.Nullable.return({
          bla: "bla",
        }),
      [],
    )
    React.null
  })
}

Before this change

module ForwardRef = {
  type props<'ref> = {ref?: 'ref}

  let make = (_: props<ReactDOM.Ref.currentDomRef>, ref) => {
    React.useImperativeHandle1(
      ref,
      () =>
        Js.Nullable.return({
          bla: "bla",
        }),
      [],
    )
    React.null
  }
  let make = React.forwardRef({
    let \"ForwardRefWithoutAnnotation$ForwardRef" = (props: props<_>, ref) => make(props, ref)

    \"ForwardRefWithoutAnnotation$ForwardRef"
  })
}

After this chage

module ForwardRef = {
  type props<'ref> = {ref?: 'ref}

  let make = (_: props<'ref>, ref: Js.Nullable.t<'ref>) => {
    React.useImperativeHandle1(
      ref,
      () =>
        Js.Nullable.return({
          bla: "bla",
        }),
      [],
    )
    React.null
  }
  let make = React.forwardRef({
    let \"ForwardRefWithoutAnnotation$ForwardRef" = (props: props<_>, ref) => make(props, ref)

    \"ForwardRefWithoutAnnotation$ForwardRef"
  })
}

[mununki]

It looks like I implemented unnecessary handling in the initial version of JSX4. This handling is unnecessary because we typically use the labeled ~ref in the interface of React.forwardRef implementations. Please see the tests I've added. 34d17b7

[jfrolich]

Amazing 🙌

[cristianoc]

Go ahead if this is ready to go.