simple support to the Partial<T> annotation

[cipolleschi]

Summary:
This feature allows using $Partial<Obj> in flow and Partial<Obj> in TypeScript based on the spec mentioned here: https://flow.org/en/docs/types/utilities/#toc-partial.

We currently only allow passing an Obj to Partial so

export type SomeObj = {
  a: string,
  b?: boolean,
};

export type PartialSomeObj = Partial<SomeObj>;

should work.
and also-

export type PartialSomeObj = Partial<{
  a: string,
  b?: boolean,
}>;

But not

export type PartialSomeObj = Partial<Partial<{
  a: string,
  b?: boolean,
}>>;

This can be improved in the future by a recursive unwrapping of the value inside the Partial annotation.

Changelog:
[General] [Added] - Allow the use of "Partial" in Turbo Module specs.

Reviewed By: christophpurrer, cipolleschi

Differential Revision: D42640880

[facebook-github-bot]

This pull request was exported from Phabricator. Differential Revision: D42640880

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
android	hermes	arm64-v8a	8,462,911	+0
android	hermes	armeabi-v7a	7,783,489	+0
android	hermes	x86	8,936,172	+0
android	hermes	x86_64	8,794,233	+0
android	jsc	arm64-v8a	9,648,873	+0
android	jsc	armeabi-v7a	8,383,370	+0
android	jsc	x86	9,711,124	+0
android	jsc	x86_64	10,188,137	+0

Base commit: 2bfb53c
Branch: main