message: docs: fixing custom implementations of utitiy apis
diff: @@ -181,7 +181,25 @@ The `IgnoringErrorApi` would then be imported in the app, and wired up like
  this:
  ```ts
  -builder.add(errorApiRef, new IgnoringErrorApi());
  +const app = createApp({
  + apis: [
  + /* ApiFactories */
  + createApiFactory(errorApiRef, new IgnoringErrorApi())
  +
  + // OR
  + // if you have dependencies inside your additional API you can use the object form
  + createApiFactory({
  + api: errorApiRef,
  + deps: { configApi: configApiRef },
  + factory({ configApi }) {
  + return new IgnoringErrorApi({
  + reportingUrl: configApi.getString('error.reportingUrl'),
  + });
  + },
  + }),
  + ],
  + // ... other options
  +});
  ```
  Note that the above line will cause an error if `IgnoreErrorApi` does not fully
  