Cloudflare_filter and cloudflare_firewall_rule migration

According to the documentation Replace your configuration using cf-terraforming command cf-terraforming generate --zone <ZONE_ID> --resource-type "cloudflare_ruleset" should automatically convert firewall rules created by cloudflare_firewall_rule and coudflare_filter to cloudflare_ruleset and give output which will be later used for importing. In reality, the command just outputs the resources that are already created by cloudflare_ruleset and a few other resources that are managed by Cloudflare.

Am I understanding something wrong or the documentation is not correct? Should I manually convert the deprecated resources to new ones and run terraform plan/apply?