MDL-80984 gradepenalty: define type language strings, add to standard.

lang/en/plugin.php

@@ -156,6 +156,8 @@ $string['type_gradeexport'] = 'Grade export method';
 $string['type_gradeexport_plural'] = 'Grade export methods';
 $string['type_gradeimport'] = 'Grade import method';
 $string['type_gradeimport_plural'] = 'Grade import methods';
+$string['type_gradepenalty'] = 'Grade penalty';
+$string['type_gradepenalty_plural'] = 'Grade penalties';
 $string['type_gradereport'] = 'Gradebook report';
 $string['type_gradereport_plural'] = 'Gradebook reports';
 $string['type_gradingform'] = 'Advanced grading method';

lib/plugins.json

@@ -221,6 +221,9 @@
             "direct",
             "xml"
         ],
+        "gradepenalty": [
+            "duedate"
+        ],
         "gradereport": [
             "grader",
             "history",