Merge pull request #4074 from qiansen1386/patch-8

small mistakes in service locator guide.

docs/guide/concept-service-locator.md

@@ -34,7 +34,7 @@ $locator->set('db', [
     'password' => '',
 ]);
 
-// register "db" using an anonymous function that builds a component
+// register "search" using an anonymous function that builds a component
 $locator->set('search', function () {
     return new app\components\SolrService;
 });