message: docs: Update techdocs backend instructions to use latest factory methods
  Smaller than before <3
diff: @@ -72,12 +72,8 @@ add the following
  ```typescript
  import {
  createRouter,
  - DirectoryPreparer,
  Preparers,
  Generators,
  - TechdocsGenerator,
  - CommonGitPreparer,
  - UrlPreparer,
  Publisher,
  } from '@backstage/plugin-techdocs-backend';
  import { PluginEnvironment } from '../types';
  @@ -90,30 +86,25 @@ export default async function createPlugin({
  reader,
  }: PluginEnvironment) {
  // Preparers are responsible for fetching source files for documentation.
  - const preparers = new Preparers();
  -
  - const directoryPreparer = new DirectoryPreparer(logger);
  - preparers.register('dir', directoryPreparer);
  -
  - const commonGitPreparer = new CommonGitPreparer(logger);
  - preparers.register('github', commonGitPreparer);
  - preparers.register('gitlab', commonGitPreparer);
  - preparers.register('azure/api', commonGitPreparer);
  -
  - const urlPreparer = new UrlPreparer(reader, logger);
  - preparers.register('url', urlPreparer);
  + const preparers = await Preparers.fromConfig(config, {
  + logger,
  + reader,
  + });
  // Generators are used for generating documentation sites.
  - const generators = new Generators();
  - const techdocsGenerator = new TechdocsGenerator(logger, config);
  - generators.register('techdocs', techdocsGenerator);
  + const generators = await Generators.fromConfig(config, {
  + logger,
  + });
  - // Publishers are used for
  + // Publisher is used for
  // 1. Publishing generated files to storage
  // 2. Fetching files from storage and passing them to TechDocs frontend.
  - const publisher = Publisher.fromConfig(config, logger, discovery);
  + const publisher = await Publisher.fromConfig(config, {
  + logger,
  + discovery,
  + });
  - // Docker client used by the generators.
  + // Docker client (conditionally) used by the generators, based on techdocs.generators config.
  const dockerClient = new Docker();
  return await createRouter({
  