Elaborate lint explanation

Jules-Bertholet · Jules-Bertholet · commit 481d3a1293b0 · 2025-09-30T10:05:20.000-04:00
diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs
@@ -705,7 +705,7 @@ declare_lint! {
     ///
     /// ### Explanation
     ///
-    /// These qualifiers have no effect.
+    /// These qualifiers have no effect, as `const _` items are unnameable.
     pub UNUSED_VISIBILITIES,
     Warn,
     "detect visibility qualifiers on `const _` items"
