type WritableDraft is not exported anywhere in dist, this causes build type declaration files with Draft finally fall back to raw and causing the type declaration exceeds max token length

[JodoZT]

🐛 Bug Report

A clear and concise description of what the bug is. When using Draft with object type in our code and build type declaration files from tsc, it will extract the T object type to raw object type because the WritableDraft is not exported from immer dist.

Link to repro

A bug report without a reproduction is not a bug report. Failing to follow this templately is likely to result in an immediate close & lock of the issue.

CodeSandbox link Run pnpm run build-types to build type declarations to types folder

To Reproduce

Steps to reproduce the behavior:

1. import Draft type from immer
2. Write function with Draft type
3. Build type declaration for the .ts file

   
   import type { Draft } from 'immer'

export interface A { a: number }

export function draft(t: T): Draft { return t as Draft }

const a: A = { a: 1, }

export const draftA = draft(a)

## Observed behavior
The generated type declaration file is:

import type { Draft } from 'immer'; export interface A { a: number; } export declare function draft(t: T): Draft; // Here it uses raw A definition, which can be very long export declare const draftA: { a: number; };

## Expected behavior

import type { Draft, WritableDraft } from 'immer'; export interface A { a: number; } export declare function draft(t: T): Draft; // Here it should be WritableDraft instead of raw definition of type A export declare const draftA: WritableDraft;

## Environment
immer@^10

- **Immer version:**
- [x] I filed this report against the _latest_ version of Immer