update TaskToolSet tool params

Author: VascoSch92

sdk/guides/task-tool-set.mdx

@@ -136,7 +136,6 @@ When the parent agent calls the task tool, it provides these parameters:
 | `subagent_type` | `str` | No | Which registered agent type to use (default: `"default"`) |
 | `description` | `str` | No | Short label (3-5 words) for display and tracking |
 | `resume` | `str` | No | Task ID from a previous invocation to continue |
-| `max_turns` | `int` | No | Maximum agent iterations before stopping (default: 500) |
 
 ## Task Observation