import-types preset does not add import when documents is not set

Following scenario:

• types are generated by typescript plugin into types.ts
• resolvers are generated typescript-resolver into resolvers.ts
  • referencing types.ts using the import-types preset
  • the all type references re properly prefixed with Types
  • but the import statement is not added to the top of the file
    • `import * as Types from './types'

After reviewing the code of the import-types preset I think the issue is that the import is only added when the documents key is set: https://github.com/dotansimha/graphql-code-generator/blob/22c1d235fb983f6b44059b8e9445ccdb85ad6bcf/packages/presets/import-types/src/index.ts#L67

To Reproduce I have created a code sandbox to reproduce this issue:

• When uncommenting the documents section the import statement is properly added t resolvers.ts
• If its commented out no import statement is added to resolvers.ts https://codesandbox.io/s/practical-sun-w9zps?file=/codegen.yml

Additional Info

Why separate types and resolvers: The types in types.ts are shared between client and server. Hence resolver definitions shouldn't be contained in this file

Why not include document key in root: Server and client execute different operations. Hence documents are provided on generator level individually.

Note: For anyone finding this there is a workaround to get this working. One needs to use the add plugin to manually prepend the import statement. Please note that is in addition to using the import-types preset which ensures the types are all type usage is prefixed with Types.:

    preset: import-types
    presetConfig:
      typesPath: '@shared/types'
    plugins:
      - add:
          content: "import type * as Types from '@shared/types';"
      - typescript-resolvers