document response in modelfile template variables (#1428)

docs/modelfile.md

@@ -156,11 +156,12 @@ PARAMETER <parameter> <parametervalue>
 
 #### Template Variables
 
-| Variable        | Description                                                                                                   |
-| --------------- | ------------------------------------------------------------------------------------------------------------- |
-| `{{ .System }}` | The system message used to specify custom behavior, this must also be set in the Modelfile as an instruction. |
-| `{{ .Prompt }}` | The incoming prompt, this is not specified in the model file and will be set based on input.                  |
-| `{{ .First }}`  | A boolean value used to render specific template information for the first generation of a session.           |
+| Variable          | Description                                                                                                   |
+| ----------------- | ------------------------------------------------------------------------------------------------------------- |
+| `{{ .System }}`   | The system message used to specify custom behavior, this must also be set in the Modelfile as an instruction. |
+| `{{ .Prompt }}`   | The incoming prompt, this is not specified in the model file and will be set based on input.                  |
+| `{{ .Response }}` | The response from the LLM, if not specified response is appended to the end of the template.                  |
+| `{{ .First }}`    | A boolean value used to render specific template information for the first generation of a session.           |
 
 ```modelfile
 TEMPLATE """