Fix menu header parsing/serialization

PortableExecutable/NormalMenuHeader.cs

@@ -0,0 +1,25 @@
+using System.Runtime.InteropServices;
+
+namespace SabreTools.Models.PortableExecutable
+{
+    /// <summary>
+    /// Contains version information for the menu resource. The structure definition provided
+    /// here is for explanation only; it is not present in any standard header file.
+    /// </summary>
+    /// <see href="https://learn.microsoft.com/en-us/windows/win32/menurc/menuheader"/>
+    [StructLayout(LayoutKind.Sequential)]
+    public sealed class NormalMenuHeader: MenuHeader
+    {
+        /// <summary>
+        /// The version number of the menu template. This member must be equal to zero to indicate
+        /// that this is an RT_MENU created with a standard menu template.
+        /// </summary>
+        public ushort Version;
+
+        /// <summary>
+        /// The size of the menu template header. This value is zero for menus you create with a
+        /// standard menu template.
+        /// </summary>
+        public ushort HeaderSize;
+    }
+}