Reflect TextLayout and ComputedTextBlock (#16296)

# Objective

- Fix panic when saving/loading scenes with text nodes due to missing
Reflect implementations.

crates/bevy_text/src/lib.rs

@@ -116,6 +116,8 @@ impl Plugin for TextPlugin {
             .register_type::<TextColor>()
             .register_type::<TextSpan>()
             .register_type::<TextBounds>()
+            .register_type::<TextLayout>()
+            .register_type::<ComputedTextBlock>()
             .init_asset_loader::<FontLoader>()
             .init_resource::<FontAtlasSets>()
             .init_resource::<TextPipeline>()

crates/bevy_text/src/text.rs

@@ -28,7 +28,8 @@ impl Default for CosmicBuffer {
 /// A sub-entity of a [`ComputedTextBlock`].
 ///
 /// Returned by [`ComputedTextBlock::entities`].
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Copy, Clone, Reflect)]
+#[reflect(Debug)]
 pub struct TextEntity {
     /// The entity.
     pub entity: Entity,
@@ -41,7 +42,8 @@ pub struct TextEntity {
 /// See [`TextLayout`].
 ///
 /// Automatically updated by 2d and UI text systems.
-#[derive(Component, Debug, Clone)]
+#[derive(Component, Debug, Clone, Reflect)]
+#[reflect(Component, Debug, Default)]
 pub struct ComputedTextBlock {
     /// Buffer for managing text layout and creating [`TextLayoutInfo`].
     ///
@@ -49,6 +51,7 @@ pub struct ComputedTextBlock {
     /// `TextLayoutInfo`. If you want to control the buffer contents manually or use the `cosmic-text`
     /// editor, then you need to not use `TextLayout` and instead manually implement the conversion to
     /// `TextLayoutInfo`.
+    #[reflect(ignore)]
     pub(crate) buffer: CosmicBuffer,
     /// Entities for all text spans in the block, including the root-level text.
     ///