message: Tweak search code ownership.
diff: /plugins/search-* @backstage/techdocs-core
  /plugins/techdocs @backstage/techdocs-core
  /plugins/techdocs-backend @backstage/techdocs-core
  +/packages/search-common @backstage/techdocs-core
  /packages/techdocs-common @backstage/techdocs-core
  /.changeset/cost-insights-* @backstage/silver-lining
  +/.changeset/search-* @backstage/techdocs-core
  /.changeset/techdocs-* @backstage/techdocs-core
  