Disable `[new-without-default]` for new() methods that are marked with '#[doc(hidden)]'

Fixes issue #8152

clippy_lints/src/new_without_default.rs

@@ -85,6 +85,10 @@ fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_>) {
                             // can't be implemented for unsafe new
                             return;
                         }
+                        if clippy_utils::is_doc_hidden(cx.tcx.hir().attrs(id)) {
+                            // shouldn't be implemented when it is hidden in docs
+                            return;
+                        }
                         if impl_item
                             .generics
                             .params

tests/ui/new_without_default.rs

@@ -201,4 +201,14 @@ pub fn new() -> Self {
     }
 }
 
+// see issue #8152
+// This should not create any lints
+pub struct DocHidden;
+impl DocHidden {
+    #[doc(hidden)]
+    pub fn new() -> Self {
+        DocHidden
+    }
+}
+
 fn main() {}