IFontAtlas API9 compat: support reading GameFontHandle.ImFont during UiBuilder.After/BuildFonts

Dalamud/Utility/Api10ToDoAttribute.cs

@@ -0,0 +1,19 @@
+namespace Dalamud.Utility;
+
+/// <summary>
+/// Utility class for marking something to be changed for API 10, for ease of lookup.
+/// </summary>
+[AttributeUsage(AttributeTargets.All, Inherited = false)]
+internal sealed class Api10ToDoAttribute : Attribute
+{
+    /// <summary>
+    /// Marks that this exists purely for making API 9 plugins work.
+    /// </summary>
+    public const string DeleteCompatBehavior = "Delete. This is for making API 9 plugins work.";
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="Api10ToDoAttribute"/> class.
+    /// </summary>
+    /// <param name="what">The explanation.</param>
+    public Api10ToDoAttribute(string what) => _ = what;
+}