Avoid useless allocation + keep track of the parse error

Author: o0Ignition0o

graphql_client_codegen/src/codegen.rs

@@ -167,7 +167,8 @@ fn generate_scalar_definitions<'a, 'schema: 'a>(
 fn render_derives<'a>(derives: impl Iterator<Item = &'a str>) -> impl quote::ToTokens {
     let idents = derives.map(|s| {
         syn::parse_str::<syn::Path>(s)
-            .expect(format!("couldn't parse {} as a derive Path", s).as_str())
+            .map_err(|e| format!("couldn't parse {} as a derive Path: {}", s, e))
+            .unwrap()
     });
 
     quote!(#[derive(#(#idents),*)])