cli: Fix output of `rad auth`

The `rad help` command was not the right one.

radicle-cli/examples/rad-auth.md

@@ -14,7 +14,7 @@ Initializing your radicle 👾 identity
 
 To create a Radicle repository, run `rad init` from a Git repository with at least one commit.
 To clone a repository, run `rad clone <rid>`. For example, `rad clone rad:z3gqcJUoA1n9HaHKufZs5FCSGazv5` clones the Radicle 'heartwood' repository.
-To get a list of all commands, run `rad help`.
+To get a list of all commands, run `rad`.
 ```
 
 You can get the above information at all times using the `self` command:

radicle-cli/src/commands/auth.rs

@@ -157,7 +157,7 @@ pub fn init(options: Options) -> anyhow::Result<()> {
     );
     term::info!(
         "To get a list of all commands, run {}.",
-        term::format::command("rad help"),
+        term::format::command("rad"),
     );
 
     Ok(())