refactor: reuse the functions inside the computed properties

Sources/MarkdownUI/Theme/BlockStyle/ListMarkerConfiguration.swift

@@ -15,59 +15,37 @@ public struct ListMarkerConfiguration {
 extension BlockStyle where Configuration == ListMarkerConfiguration {
   /// A list marker style that uses decimal numbers beginning with 1.
   public static var decimal: Self {
-    BlockStyle { configuration in
-      Text("\(configuration.itemNumber).")
-        .monospacedDigit()
-        .relativeFrame(minWidth: .em(1.5), alignment: .trailing)
-    }
+    decimal(minWidth: .em(1.5), alignment: .trailing)
   }
 
   /// A list marker style that uses uppercase roman numerals beginning with `I`.
   public static var upperRoman: Self {
-    BlockStyle { configuration in
-      Text(configuration.itemNumber.roman + ".")
-        .relativeFrame(minWidth: .em(1.5), alignment: .trailing)
-    }
+    upperRoman(minWidth: .em(1.5), alignment: .trailing)
   }
 
   /// A list marker style that uses lowercase roman numerals beginning with `i`.
   public static var lowerRoman: Self {
-    BlockStyle { configuration in
-      Text(configuration.itemNumber.roman.lowercased() + ".")
-        .relativeFrame(minWidth: .em(1.5), alignment: .trailing)
-    }
+    lowerRoman(minWidth: .em(1.5), alignment: .trailing)
   }
 
   /// A list marker style that uses a dash.
   public static var dash: Self {
-    BlockStyle { _ in
-      Text("-")
-        .relativeFrame(minWidth: .em(1.5), alignment: .trailing)
-    }
+    dash(minWidth: .em(1.5), alignment: .trailing)
   }
 
   /// A list marker style that uses a filled circle.
   public static var disc: Self {
-    BlockStyle { _ in
-      ListBullet.disc
-        .relativeFrame(minWidth: .em(1.5), alignment: .trailing)
-    }
+    disc(minWidth: .em(1.5), alignment: .trailing)
   }
 
   /// A list marker style that uses a hollow circle.
   public static var circle: Self {
-    BlockStyle { _ in
-      ListBullet.circle
-        .relativeFrame(minWidth: .em(1.5), alignment: .trailing)
-    }
+    circle(minWidth: .em(1.5), alignment: .trailing)
   }
 
   /// A list marker style that uses a filled square.
   public static var square: Self {
-    BlockStyle { _ in
-      ListBullet.square
-        .relativeFrame(minWidth: .em(1.5), alignment: .trailing)
-    }
+    square(minWidth: .em(1.5), alignment: .trailing)
   }
 
   /// A list marker style that alternates between disc, circle, and square, depending on the list level.
@@ -78,6 +56,7 @@ extension BlockStyle where Configuration == ListMarkerConfiguration {
         .makeBody(configuration: configuration)
     }
   }
+}
 
 // MARK: Dynamic