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>

editor/src/lib.rs

@@ -3,6 +3,7 @@ extern crate graphite_proc_macros;
 // `macro_use` puts these macros into scope for all descendant code files
 #[macro_use]
 mod macros;
+mod generate_ts_types;
 #[macro_use]
 extern crate log;