Hide the start-session command (#984)

Until it's ready. See #983

src/cmd_start_session.rs

@@ -3,7 +3,16 @@ use std::net::SocketAddr;
 use anyhow::Result;
 use clap::Parser;
 
-/// Starts a modeling session
+/// Starts a modeling session.
+///
+/// This command starts a server on localhost (on the configurable interface), and
+/// waits to receive KCL programs over that server. It also connects to the KittyCAD
+/// API and keeps the connection alive until this process is stopped. When it receives
+/// a KCL program over the local server, it executes it using the long-lived KittyCAD
+/// connection.
+///
+/// This subcommand is designed to be used with `zoo kcl snapshot --session localhost:3333`,
+/// which will reuse the existing connection started by `zoo start-session localhost:3333`.
 #[derive(Parser, Debug, Clone)]
 #[clap(verbatim_doc_comment)]
 pub struct CmdStartSession {

src/main.rs

@@ -142,6 +142,8 @@ enum SubCommand {
     Kcl(cmd_kcl::CmdKcl),
     Ml(cmd_ml::CmdMl),
     Say(cmd_say::CmdSay),
+    // Hide until <https://github.com/KittyCAD/cli/issues/983> is done.
+    #[clap(hide = true)]
     StartSession(cmd_start_session::CmdStartSession),
     Open(cmd_open::CmdOpen),
     Update(cmd_update::CmdUpdate),