Retire layer paths used throughout the code (#1531)

* Part 1

* Part 2

* Part 3

* Part 4

* Part 5

* Part 6

* Part 7

* Part 8

editor/src/messages/prelude.rs

@@ -56,6 +56,9 @@ pub use graphite_proc_macros::*;
 
 pub use std::collections::{HashMap, HashSet, VecDeque};
 
+// TODO: Convert from a type alias to a newtype
+pub type DocumentId = u64;
+
 pub trait Responses {
 	fn add(&mut self, message: impl Into<Message>);