MDL-82158 core_cache: Coding style fixes

cache/tests/fixtures/cache_phpunit_dummy_datasource_versionable.php

@@ -14,6 +14,8 @@
 // You should have received a copy of the GNU General Public License
 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
 
+use core_cache\versionable_data_source_interface;
+
 /**
  * A dummy datasource which supports versioning.
  *
@@ -21,8 +23,9 @@
  * @copyright 2021 The Open University
  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
-class cache_phpunit_dummy_datasource_versionable extends cache_phpunit_dummy_datasource
-        implements cache_data_source_versionable {
+class cache_phpunit_dummy_datasource_versionable extends cache_phpunit_dummy_datasource implements
+    versionable_data_source_interface
+{
     /** @var array Data in cache */
     protected $data = [];
 
@@ -35,8 +38,7 @@ class cache_phpunit_dummy_datasource_versionable extends cache_phpunit_dummy_dat
      * @param cache_definition $definition
      * @return cache_phpunit_dummy_datasource New object
      */
-    public static function get_instance_for_cache(cache_definition $definition):
-            cache_phpunit_dummy_datasource_versionable {
+    public static function get_instance_for_cache(cache_definition $definition): cache_phpunit_dummy_datasource_versionable {
         self::$lastinstance = new cache_phpunit_dummy_datasource_versionable();
         return self::$lastinstance;
     }
@@ -81,4 +83,3 @@ class cache_phpunit_dummy_datasource_versionable extends cache_phpunit_dummy_dat
         return $value->data;
     }
 }
-