Fix rustdoc tests

Author: carbotaniuman

src/librustdoc/clean/cfg/tests.rs

@@ -34,6 +34,7 @@ fn dummy_meta_item_name_value(name: &str, symbol: Symbol, kind: LitKind) -> Meta
 macro_rules! dummy_meta_item_list {
     ($name:ident, [$($list:ident),* $(,)?]) => {
         MetaItem {
+            unsafety: Unsafe::No,
             path: Path::from_ident(Ident::from_str(stringify!($name))),
             kind: MetaItemKind::List(thin_vec![
                 $(