Wrap the intermediate Registry in an IntermediateContext.

This is currently just to maintain consistency with the render phase's RenderContext but in the future it should allow us to include immutable data that is not locked behind the ArcMutex.

src/intermediate/object.rs

@@ -63,9 +63,9 @@ pub(crate) enum IObject {
     Timestamp(ITimestamp),
 }
 
-iselector!(IObject, Object, original, registry, {
+iselector!(IObject, Object, original, intermediate_context, {
     iitem!(
-        registry,
+        intermediate_context,
         original,
         (organic::types::Object::Bold, IObject::Bold, IBold),
         (organic::types::Object::Italic, IObject::Italic, IItalic),