Fix ambigous names of generated struct+module

If a camel case query name like "ping_query" is used,
the generated code fails. Fixed by using `to_camel_case`
for the struct name, while the module name still uses `to_snake_case`.

Even for a single word query name like "ping" that should work.

Signed-off-by: David Graeff <david.graeff@web.de>

graphql_client_codegen/src/generated_module.rs

@@ -28,7 +28,7 @@ impl<'a> GeneratedModule<'a> {
         let module_name = Ident::new(&self.operation.name.to_snake_case(), Span::call_site());
         let module_visibility = &self.options.module_visibility();
         let operation_name_literal = &self.operation.name;
-        let operation_name_ident = Ident::new(&self.operation.name, Span::call_site());
+        let operation_name_ident = Ident::new(&self.operation.name.to_camel_case(), Span::call_site());
 
         // Force cargo to refresh the generated code when the query file changes.
         let query_include = self
@@ -52,6 +52,7 @@ impl<'a> GeneratedModule<'a> {
         };
 
         Ok(quote!(
+            #[allow(dead_code)]
             #struct_declaration
 
             #module_visibility mod #module_name {