fix activity maindocuments

entity/Activity_entity/entityfields/maindocuments/children/assignmentname_param/code.js

+import("system.result");
+
+result.string("DOCUMENT");
\ No newline at end of file

entity/Activity_entity/entityfields/maindocuments/children/assignmentrowid_param/code.js

+import("system.result");
+import("system.vars");
+
+result.string(vars.get("$field.ACTIVITYID"));
\ No newline at end of file

entity/Activity_entity/entityfields/maindocuments/children/assignmenttable_param/code.js

+import("system.result");
+
+result.string("ACTIVITY");
\ No newline at end of file