Fix: Allow missing docs for test modules (#10893)

crates/metrics/metrics-derive/tests/metrics.rs

@@ -1,3 +1,4 @@
+#![allow(missing_docs)]
 use metrics::{
     Counter, Gauge, Histogram, Key, KeyName, Label, Metadata, Recorder, SharedString, Unit,
 };

crates/metrics/metrics-derive/tests/trybuild.rs

@@ -1,3 +1,4 @@
+#![allow(missing_docs)]
 #[test]
 fn compile_test() {
     let t = trybuild::TestCases::new();