Add missing Russian translations

Resources/translations/SonataAdminBundle.ru.xliff

@@ -468,11 +468,11 @@
             </trans-unit>
             <trans-unit id="read_more">
                 <source>read_more</source>
-                <target>read_more</target>
+                <target>Читать далее</target>
             </trans-unit>
             <trans-unit id="read_less">
                 <source>read_less</source>
-                <target>read_less</target>
+                <target>Закрыть</target>
             </trans-unit>
         </body>
     </file>