Add tag relation type display_subject

src/enums/MDTagRelationType.php

@@ -17,6 +17,7 @@ enum MDTagRelationType implements MDValueEnumInterface, JsonSerializable {
     case object_type;
     case material;
     case technique;
+    case display_subject;
 
     /**
      * Returns a value of this type based on a string.
@@ -32,6 +33,7 @@ public static function fromString(string $input):MDTagRelationType {
             'object_type' => self::object_type,
             'material' => self::material,
             'technique' => self::technique,
+            'display_subject' => self::display_subject,
             default => throw new MDpageParameterNotFromListException("Unknown tag relation type"),
         };
 
@@ -51,6 +53,7 @@ public static function fromInt(int $input):MDTagRelationType {
             1 => self::object_type,
             2 => self::material,
             3 => self::technique,
+            4 => self::display_subject,
             default => throw new MDpageParameterNotFromListException("Unknown tag relation type"),
         };
 
@@ -115,6 +118,7 @@ public function toInt():int {
             self::object_type => 1,
             self::material => 2,
             self::technique => 3,
+            self::display_subject => 4,
             // default => throw new MDpageParameterNotFromListException("Unknown tag relation type"),
         };