More comments and tweak details (#33)

Co-authored-by: Alice Ryhl <alice@ryhl.io>

src/bin/server.rs

@@ -1,3 +1,11 @@
+//! mini-redis server.
+//!
+//! This file is the entry point for the server implemented in the library. It
+//! performs command line parsing and passes the arguments on to
+//! `mini_redis::server`.
+//!
+//! The `clap` crate is used for parsing arguments.
+
 use mini_redis::{server, DEFAULT_PORT};
 
 use clap::Clap;