rust/pv: Lower most lints to warn

Lower the lint level to warn for the styling lints.
This avoids compile issues during packaging for newer tooling with
potential more lint findings.
Still deny compiling if a public symbol has no documentation.

Fixes: https://github.com/ibm-s390-linux/s390-tools/issues/173
Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>

rust/pv/src/lib.rs

@@ -2,8 +2,8 @@
 //
 // Copyright IBM Corp. 2023, 2024
 
-#![deny(
-    missing_docs,
+#![deny(missing_docs)]
+#![warn(
     missing_debug_implementations,
     trivial_numeric_casts,
     unstable_features,

rust/pv_core/src/lib.rs

@@ -1,8 +1,8 @@
 // SPDX-License-Identifier: MIT
 //
 // Copyright IBM Corp. 2023, 2024
-#![deny(
-    missing_docs,
+#![deny(missing_docs)]
+#![warn(
     missing_debug_implementations,
     trivial_numeric_casts,
     unstable_features,