message: Add Config API interface jsdoc
diff: import { ApiRef, createApiRef } from '../system';
  import { Config } from '@backstage/config';
  -// Using interface to make the ConfigApi name show up in docs
  +/**
  + * The Config API is used to provide a mechanism to access the
  + * runtime configuration of the system.
  + */
  export type ConfigApi = Config;
  export const configApiRef: ApiRef<ConfigApi> = createApiRef({
  