Add documentation for documentation server

README.md

@@ -5,5 +5,5 @@ To read the documentation, run
 ```shell
 $ git clone --branch rewrite https://git.nyeki.dev/payphone/payphone.git
 $ cd payphone
-$ cargo doc --open --no-deps
+$ cargo run -- docs
 ```

src/main.rs

@@ -74,6 +74,15 @@
 //! consistency and readability.
 //!
 //! More documentation about each group can be found in the respective submodule's documentation.
+//! 
+//! # Documentation Server
+//! 
+//! Payphone has a built-in documentation server that serves the project's documentation and refreshes
+//! it on changes. To start the documentation server, run the following command:
+//! 
+//! ```shell
+//! $ cargo run -- docs
+//! ```
 
 use std::{net::SocketAddr, path::Path, process::Command, sync::mpsc};