React module exports should not be an exact object

Summary:
The exports of the `react` module should not be an exact object, as the exports can have unknown properties.

E.g. experimental features: https://www.internalfb.com/code/search?q=filepath%3Ahtml%2Fjs%2F%7Chtml%2Fintern%2Fjs%2F%7Chtml%2Fshared%2F%20repo%3Awww%20React.unstable_&hide_uninteresting=false&hide_tests=false

This doesn't currently matter much, but is technically more accurate and might have an effect with some future changes I might make

Changelog: [minor] React default exports are now inexact, as technically this can include unknown properties (experimental features)

Reviewed By: samwgoldman

Differential Revision: D34337501

fbshipit-source-id: e3172a2d18993745bd4bed8161b239b226a796ad

lib/react.js

@@ -425,7 +425,7 @@ declare module react {
     timeoutMs: number,
   |};
 
-  declare export default {|
+  declare export default {
     +DOM: typeof DOM,
     +PropTypes: typeof PropTypes,
     +version: typeof version,
@@ -460,7 +460,8 @@ declare module react {
     +useTransition: typeof useTransition,
     +useDeferredValue: typeof useDeferredValue,
     +startTransition: typeof startTransition,
-  |};
+    ...
+  };
 }
 
 // TODO Delete this once https://github.com/facebook/react/pull/3031 lands

tests/automatic_require_default/automatic_require_default.exp

@@ -21,8 +21,8 @@ Cannot get `React.NotAType` because property `NotAType` is missing in module `re
                     ^^^^^^^^
 
 References:
-   <BUILTINS>/react.js:469:27
-   469|   declare module.exports: $Exports<'react'>;
+   <BUILTINS>/react.js:470:27
+   470|   declare module.exports: $Exports<'react'>;
                                   ^^^^^^^^^^^^^^^^^ [1]
 
 

tests/new_react/new_react.exp

@@ -1319,13 +1319,13 @@ Cannot get `React.PropTypes.string.inRequired` because property `inRequired` (di
                                               ^^^^^^^^^^
 
 References:
-   <BUILTINS>/react.js:478:39
+   <BUILTINS>/react.js:479:39
                                               v
-   478| type ReactPropsChainableTypeChecker = {
-   479|   (props: any, propName: string, componentName: string, href?: string): ?Error,
-   480|   isRequired: ReactPropsCheckType,
-   481|   ...
-   482| };
+   479| type ReactPropsChainableTypeChecker = {
+   480|   (props: any, propName: string, componentName: string, href?: string): ?Error,
+   481|   isRequired: ReactPropsCheckType,
+   482|   ...
+   483| };
         ^ [1]