Add documentation for granite 4 tool calling (vllm-project#26175)

Signed-off-by: Max de Bayser <mbayser@br.ibm.com>

Author: maxdebayser

docs/features/tool_calling.md

@@ -191,10 +191,14 @@ VLLM also provides a pythonic and JSON-based chat template for Llama 4, but pyth
 
 For Llama 4 model, use `--tool-call-parser llama4_pythonic --chat-template examples/tool_chat_template_llama4_pythonic.jinja`.
 
-#### IBM Granite
+### IBM Granite
 
 Supported models:
 
+* `ibm-granite/granite-4.0-h-small` and other Granite 4.0 models
+
+    Recommended flags: `--tool-call-parser hermes`
+
 * `ibm-granite/granite-3.0-8b-instruct`
 
     Recommended flags: `--tool-call-parser granite --chat-template examples/tool_chat_template_granite.jinja`