cli/self: `--nid` deprecation warning to stderr

Printing the warning to standard output breaks scripts.

Instead, print to standard error.

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Deprecations
 
+- The option `rad self --nid` was deprecated in favor of `rad status --only nid`
 ## New Features
 
 - `rad clone` now supports the flag `--bare` which works analoguously to

crates/radicle-cli/examples/rad-self.md

@@ -26,10 +26,14 @@ did:key:z6MknSLrJoTcukLrE435hVNQT4JUhbvWLX4kUzqkEStBU8Vi
 
 ```
 $ rad self --nid
-! Warning: The option `--nid` is deprecated, please use `rad node status --only nid` instead.
 z6MknSLrJoTcukLrE435hVNQT4JUhbvWLX4kUzqkEStBU8Vi
 ```
 
+``` (stderr)
+$ rad self --nid
+! Deprecated: The command/option `rad self --nid` is deprecated and will be removed. Please use `rad node status --only nid` instead.
+```
+
 ```
 $ rad self --ssh-key
 ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIHahWSBEpuT1ESZbynOmBNkLBSnR32Ar4woZqSV2YNH1

crates/radicle-cli/src/commands/self.rs

@@ -100,9 +100,7 @@ pub fn run(options: Options, ctx: impl term::Context) -> anyhow::Result<()> {
             term::print(profile.config.alias());
         }
         Show::NodeId => {
-            term::warning(
-                "The option `--nid` is deprecated, please use `rad node status --only nid` instead.",
-            );
+            crate::warning::deprecated("rad self --nid", "rad node status --only nid");
             term::print(
                 Node::new(profile.socket())
                     .nid()