fix: nodes field returning nil on nested collections (#484)

The upstream PR ent/contrib#602 appears to have missed adding the check
for the `nodes` field being used in the collections template. This is
used when you call a collection from another collection, for example:

```
query {
  loadBalancer(id: "lb-123"){
    ports {
      nodes {
        pools {
          nodes {
            id
          }
        }
      }
    }
  }
}
```

Before this fix the `pools.nodes` would come back as an empty list, with
this fix it's properly filled out.

Signed-off-by: Nicole Hubbard <[email protected]>

Author: nicolerenee

entx/generator.go

@@ -47,7 +47,7 @@ func WithFederation() ExtensionOption {
 // WithConnectionNodes adds the templates for adding nodes to relay connections
 func WithConnectionNodes() ExtensionOption {
 	return func(ex *Extension) error {
-		ex.templates = append(ex.templates, PaginationTemplate)
+		ex.templates = append(ex.templates, PaginationTemplate, CollectionTemplate)
 		ex.gqlSchemaHooks = append(ex.gqlSchemaHooks, addNodesToConnections)
 
 		return nil

entx/template.go

@@ -34,6 +34,9 @@ var (
 	// PaginationTemplate adds support for adding the nodes field to relay connections
 	PaginationTemplate = parseT("template/pagination.tmpl")
 
+	// CollectionTemplate adds support for adding the nodes field to relay connections
+	CollectionTemplate = parseT("template/collection.tmpl")
+
 	// TemplateFuncs contains the extra template functions used by entx.
 	TemplateFuncs = template.FuncMap{
 		"contains":                          strings.Contains,