Rename the legacy Graphene crate to document-legacy (#899)

* Rename /graphene to /document-legacy

* Update names in code

website/content/contribute/_index.md

@@ -66,19 +66,19 @@ The Graphite Editor is built as a web app powered by Vue.js in the frontend and
 
 The Editor's frontend web code lives in `/frontend/src` and the backend Rust code lives in `/editor`. The web-based frontend is intended to be semi-temporary and eventually replaceable with a pure-Rust GUI frontend. Therefore, all backend code should be unaware of JavaScript or web concepts and all Editor application logic should be written in Rust not JS.
 
-### Frontend/backend communication
+### Frontend/backend communication.
 
 Frontend (JS) -> backend (Rust/wasm) communication is achieved through a thin Rust translation layer in `/frontend/wasm/editor_api.rs` which wraps the Editor backend's complex Rust data type API and provides the JS with a simpler API of callable functions. These wrapper functions are compiled by wasm-bindgen into autogenerated JS functions that serve as an entry point into the wasm.
 
 Backend (Rust) -> frontend (JS) communication happens by sending a queue of messages to the frontend message dispatcher. After the JS calls any wrapper API function to get into backend (Rust) code execution, the Editor's business logic runs and queues up `FrontendMessage`s (defined in `editor/src/frontend/frontend_message_handler.rs`) which get mapped from Rust to JS-friendly data types in `frontend/src/dispatcher/js-messages.ts`. Various JS code subscribes to these messages by calling `subscribeJsMessage(MessageName, (messageData) => { /* callback code */ });`.
 
-### Editor backend and Graphene modules
+### The Editor backend and Legacy Document modules.
 
 The Graphite Editor backend handles all the day-to-day logic and responsibilities of a user-facing interactive application. Some duties include: user input, GUI state management, viewport tool behavior, layer management and selection, and handling of multiple document tabs.
 
-The actual document (the artwork data and layers included in a saved `.graphite` file) is part of another core module located in `/graphene`. Graphene manages a document and will grow into the codebase for the full node graph system in the future. While it's OK for the Editor to read data from, or make immutable function calls upon, the Graphene document, it should never be directly mutated. Instead, messages (called Operations) should be sent to the Graphene document to request changes occur. Graphene is designed to be used by the Editor or by third-party Rust or C/C++ code directly so a careful separation of concerns between the Editor and Graphene should be considered.
+The actual document (the artwork data and layers included in a saved `.graphite` file) is part of another core module located in `/document-legacy`. The (soon-to-be-replaced) Legacy Document codebase manages a user's document. Once it is replaced, the new Document module (that will be located in `/document`) will store a document's node graph and change history. While it's OK for the Editor to read data from—or make immutable function calls upon—the user's document controlled by the Legacy Document module, it should never be directly mutated. Instead, messages (called Operations) should be sent to the document to request changes occur. The Legacy Document code is designed to be used by the Editor or by third-party Rust or C/C++ code directly so a careful separation of concerns between the Editor and Legacy Document modules should be considered.
 
-### The message bus
+### The message bus.
 
 Every part of the Graphite stack works based on the concept of message passing. Messages are pushed to the front or back of a queue and each one is processed by the module's dispatcher in the order encountered. Only the dispatcher owns a mutable reference to update its module's state.
 
@@ -92,7 +92,7 @@ Because this is cumbersome, we have a proc macro `#[child]` that automatically i
 
 </details>
 
-## Debugging
+## Debugging.
 
 Use the browser console (<kbd>F12</kbd>) to check for warnings and errors. Use the Rust macro `debug!("A debug message")` to print to the browser console. These statements should be for temporary debugging. Remove them before committing to master. Print-based debugging is necessary because breakpoints are not supported in WebAssembly.
 
@@ -108,7 +108,7 @@ To also view logs of the messages dispatched by the message bus system, activate
 
 ## Contributing guide.
 
-### Code style
+### Code style.
 
 The Graphite project highly values code quality and accessibility to new contributors. Therefore, please make an effort to make your code readable and well-documented.
 
@@ -121,7 +121,7 @@ The Graphite project highly values code quality and accessibility to new contrib
 - **Imports:**  
   At the top of Rust files, please follow the convention of separating imports into three blocks, in this order:
   1. Local (`use super::` and `use crate::`)
-  2. First-party crates (e.g. `use graphene::`)
+  2. First-party crates (e.g. `use editor::`)
   3. Third-party libraries (e.g. `use std::` or `use serde::`)
 
   Combine related imports with common paths at the same depth. For example, the lines `use crate::A::B::C;`, `use crate::A::B::C::Foo;`, and `use crate::A::B::C::Bar;` should be combined into `use crate::A::B::C::{self, Foo, Bar};`. But do not combine imports at mixed path depths. For example, `use crate::A::{B::C::Foo, X::Hello};` should be split into two separate import lines. In simpler terms, avoid putting a `::` inside `{}`.
@@ -131,7 +131,7 @@ The Graphite project highly values code quality and accessibility to new contrib
 
 Additional best practices will be added here soon. Please ask @Keavon in the mean time.
 
-### Draft pull requests
+### Draft pull requests.
 
 Once you begin writing code, please open a pull request immediately and mark it as a **Draft**. Please push to this on a frequent basis, even if things don't compile or work fully yet. It's very helpful to have your work-in-progress code up on GitHub so the status of your feature is less of a mystery.