kernel: remove old doc references to arena Handles

oro-kernel/src/ring.rs

@@ -35,7 +35,7 @@ use crate::{AddrSpace, Arch, Kernel, UserHandle, instance::Instance};
 pub struct Ring<A: Arch> {
 	/// The resource ID.
 	id: u64,
-	/// The parent ring [`Handle`]. `None` if this is the root ring.
+	/// The parent ring handle, or `None` if this is the root ring.
 	parent: Option<Weak<Mutex<Ring<A>>>>,
 	/// The module [`Instance`]s on the ring.
 	pub(super) instances: Vec<Arc<Mutex<Instance<A>>>>,

oro-kernel/src/thread.rs

@@ -178,7 +178,7 @@ impl<A: Arch> Thread<A> {
 		self.id
 	}
 
-	/// Returns module instance [`Handle`] to which this thread belongs.
+	/// Returns module instance handle to which this thread belongs.
 	pub fn instance(&self) -> Arc<Mutex<Instance<A>>> {
 		self.instance.clone()
 	}