MDL-81333 core_communication: Coding style fixups

- Remove superflous coverage information
 - Use language string for group room name format

communication/classes/helper.php

@@ -559,6 +559,9 @@ class helper {
         string $baseroomname,
         string $groupname
     ): string {
-        return "{$groupname} ({$baseroomname})";
+        return get_string('communicationgrouproomnameformat', 'core_communication', [
+            'groupname' => $groupname,
+            'baseroomname' => $baseroomname,
+        ]);
     }
 }

communication/tests/helper_test.php

@@ -223,8 +223,6 @@ class helper_test extends \advanced_testcase {
 
     /**
      * Test format_group_room_name.
-     *
-     * @covers ::format_group_room_name
      */
     public function test_format_group_room_name(): void {
         $baseroomname = 'Course A';

lang/en/communication.php

@@ -29,6 +29,7 @@ $string['communicationroomname'] = 'Room name';
 $string['communicationroomnameinfo'] = 'If the field is left blank, the course name is used as the room name.';
 $string['communicationroompending'] = 'Your {$a} room will be ready soon.';
 $string['communicationroomready'] = 'Your {$a} room is ready.';
+$string['communicationgrouproomnameformat'] = '{$a->groupname} ({$a->baseroomname})';
 $string['managecommunicationproviders'] = 'Manage communication providers';
 $string['nocommunicationinstance'] = 'No communication instance found.';
 $string['nocommunicationprovider'] = 'No communication provider found.';