Ignore map_clone clippy lint

    warning: you are explicitly cloning with `.map()`
      --> gen/cmd/src/app.rs:72:32
       |
    72 |       let cxx_impl_annotations = matches
       |  ________________________________^
    73 | |         .get_one::<String>(CXX_IMPL_ANNOTATIONS)
    74 | |         .map(String::clone);
       | |___________________________^
       |
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#map_clone
       = note: `-W clippy::map-clone` implied by `-W clippy::all`
       = help: to override `-W clippy::all` add `#[allow(clippy::map_clone)]`
    help: consider calling the dedicated `cloned` method
       |
    72 ~     let cxx_impl_annotations = matches
    73 ~         .get_one::<String>(CXX_IMPL_ANNOTATIONS).cloned();
       |

gen/cmd/src/main.rs

@@ -9,6 +9,7 @@
     clippy::into_iter_without_iter,
     clippy::items_after_statements,
     clippy::large_enum_variant,
+    clippy::map_clone,
     clippy::match_bool,
     clippy::match_on_vec_items,
     clippy::match_same_arms,