add trailing comma

Author: danishnawab

examples/gpt-5/gpt-5_prompting_guide.ipynb

@@ -130,7 +130,7 @@
     "```\n",
     "\n",
     "### Reasoning effort\n",
-    "We provide a `reasoning_effort` parameter to control how hard the model thinks and how willingly it calls tools; the default is `medium`, but you should scale up or down depending on the difficulty of your task. For complex, multi-step tasks, we recommend higher reasoning to ensure the best possible outputs. Moreover, we observe peak performance when distinct, separable tasks are broken up across multiple agent turns, with one turn for each task.\n"
+    "We provide a `reasoning_effort` parameter to control how hard the model thinks and how willingly it calls tools; the default is `medium`, but you should scale up or down depending on the difficulty of your task. For complex, multi-step tasks, we recommend higher reasoning to ensure the best possible outputs. Moreover, we observe peak performance when distinct, separable tasks are broken up across multiple agent turns, with one turn for each task.\n",
     "### Reusing reasoning context with the Responses API\n",
     "We strongly recommend using the Responses API when using GPT-5 to unlock improved agentic flows, lower costs, and more efficient token usage in your applications.\n",
     "\n",