Support Paths in response derives.

Up until now only Idents were supported in the response_derives section,
which unfortunately wouldn't allow us to provide fully qualified names.

This commit enables Path support, and provides us with an error message
if we couldn't parse a response_derive as a valid Path.

Author: o0Ignition0o

graphql_client/tests/more_derives.rs

@@ -4,7 +4,7 @@ use graphql_client::*;
 #[graphql(
     schema_path = "tests/more_derives/schema.graphql",
     query_path = "tests/more_derives/query.graphql",
-    response_derives = "Debug, PartialEq, PartialOrd"
+    response_derives = "Debug, PartialEq, std::cmp::PartialOrd"
 )]
 pub struct MoreDerives;
 

graphql_client_codegen/src/codegen.rs

@@ -165,7 +165,10 @@ 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| Ident::new(s, Span::call_site()));
+    let idents = derives.map(|s| {
+        syn::parse_str::<syn::Path>(s)
+            .expect(format!("couldn't parse {} as a derive Path", s).as_str())
+    });
 
     quote!(#[derive(#(#idents),*)])
 }