Groundwork for integrating Specta (#949)

* add derive(specta::Type)

* use specta from git

* introduce Uuid type

* remove unnecessary specta::Type

* document export_types test

* upgrade Specta
The previous Specta branch had some hacks that were just for this project. They have all been converted into proper features so they can be merged into main.

* remove some unnecessary specta::Type uses

* add MessageDiscriminantDef explanation

* manually export types with specta

* rename 'specta.rs' to 'export_types.rs'

* rename 'export_types' to 'generate_ts_types'

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Co-authored-by: Oscar Beaumont <oscar@otbeaumont.me>

document-legacy/src/layers/text_layer.rs

@@ -17,7 +17,7 @@ mod to_path;
 /// A line, or multiple lines, of text drawn in the document.
 /// Like [ShapeLayers](super::shape_layer::ShapeLayer), [TextLayer] are rendered as
 /// [`<path>`s](https://developer.mozilla.org/en-US/docs/Web/SVG/Element/path).
-#[derive(Debug, Clone, PartialEq, Deserialize, Serialize)]
+#[derive(Debug, Clone, PartialEq, Deserialize, Serialize, specta::Type)]
 pub struct TextLayer {
 	/// The string of text, encompassing one or multiple lines.
 	pub text: String,