MED-100: Fix subplugin string

lang/en/tool_mediatime.php

@@ -45,7 +45,7 @@
 $string['privacy:metadata:tool_mediatime:usermodified'] = 'User modified';
 $string['resourcename'] = 'Resource name';
 $string['resourcename_help'] = 'The name for a resource is used internally in the library to identify the resource, but not displayed when it is used.';
-$string['subplugin_mediatimesrc_plural'] = 'Media sources';
+$string['subplugintype_mediatimesrc'] = 'Media Time source';
 $string['subplugintype_mediatimesrc_plural'] = 'Media Time sources';
 $string['tagarea_tool_mediatime'] = 'Media resources';
 $string['title'] = 'Title';