Add support for call blocks

Support for the [MiniCPM4-MCP Chat Template](https://huggingface.co/openbmb/MiniCPM4-MCP?chat_template=default) would be nice. :)

It requires support for the [call block](https://jinja.palletsprojects.com/en/stable/templates/#call) to function, @ochafik if you're the one implementing this I apologize in advance, I'm the one that made the template... :D