rust: docs: add missing newline to printing macro examples

Fix adding a newline at the end of the usage of pr_info! in the
documentation

Fixes: e3c3d34 ("docs: rust: Add description of Rust documentation test as KUnit ones")
Reported-by: Miguel Ojeda <[email protected]>
Link: #1139
Signed-off-by: Alban Kurti <[email protected]>
Reviewed-by: David Gow <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ Replaced Closes with Link since it fixes part of the issue. - Miguel ]
Signed-off-by: Miguel Ojeda <[email protected]>

Author: albankurti

Documentation/rust/testing.rst

@@ -97,7 +97,7 @@ operator are also supported as usual, e.g.:
 
 	/// ```
 	/// # use kernel::{spawn_work_item, workqueue};
-	/// spawn_work_item!(workqueue::system(), || pr_info!("x"))?;
+	/// spawn_work_item!(workqueue::system(), || pr_info!("x\n"))?;
 	/// # Ok::<(), Error>(())
 	/// ```