message: docs: fix readme links to create fetcher
diff: @@ -109,7 +109,7 @@ ReactDOM.render(
  );
  ```
  -Read more about using [`createGraphiQLFetcher`](https://github.com/graphql/graphiql/packages/tree/main/packages/graphiql-toolkit) in the readme to learn how to add headers and more.
  +Read more about using [`createGraphiQLFetcher`](https://github.com/graphql/graphiql/tree/main/packages/graphiql-toolkit/docs/create-fetcher.md) in the readme to learn how to add headers and more.
  ### Usage: UMD Bundle over CDN (Unpkg, JSDelivr, etc)
  @@ -157,7 +157,7 @@ The most minimal way to set up GraphiQL is a single index.html file:
  - the inlined styles are important for ensuring GraphiQL is visible and fills the canvas.
  - using `React.createElement` directly is belaborous, so follow the webpack instructions above for more highly customized implementation
  -- we can use `GraphiQL.createFetcher` in the UMD bundle only, so that it can be tree shaken out for modules
  +- we can use [`GraphiQL.createFetcher`](https://github.com/graphql/graphiql/tree/main/packages/graphiql-toolkit/docs/create-fetcher.md) in the UMD bundle only, so that it can be tree shaken out for modules
  ### GraphiQL for my GraphQL Service/HTTP Server/Etc
  