message: docs: fix usage of d.ts
diff: @@ -44,7 +44,7 @@ console.log(result.errors); // array of ajv error objects
  ## `manifest-json.d.ts`
  ```js
  -import {KintonePluginManifestJson} from '@teppeis/kintone-plugin-manifest-validator/manifest-json';
  +import {KintonePluginManifestJson} from '@teppeis/kintone-plugin-manifest-validator/manifest-schema';
  let manifest: KintonePluginManifestJson;
  ```
  