Fix: Refactor to avoid clippy::needless_for_each warning in derive(OpenApi) (#1423)

By refactoring the macro to generate a for loop instead of using for_each, we now produce code that is cleaner and no longer triggers this clippy warning.

Author: raimannma

utoipa-gen/src/openapi.rs

@@ -550,7 +550,9 @@ impl ToTokensDiagnostics for OpenApi<'_> {
 
                 quote! {
                     let _mods: [&dyn utoipa::Modify; #modifiers_len] = [#modifiers];
-                    _mods.iter().for_each(|modifier| modifier.modify(&mut openapi));
+                    for modifier in &_mods {
+                        modifier.modify(&mut openapi);
+                    }
                 }
             });