Fix typos in prompt example Self_ask_prompting.ipynb

Fix a couple of small typos in the examples given in the prompt.

examples/prompting/Self_ask_prompting.ipynb

@@ -152,13 +152,13 @@
         "prompt = \"\"\"\n",
         "Question: Who was the president of the united states when Mozart died?\n",
         "Are follow up questions needed?: yes.\n",
-        "Follow up: When did Mozart died?\n",
+        "Follow up: When did Mozart die?\n",
         "Intermediate answer: 1791.\n",
         "Follow up: Who was the president of the united states in 1791?\n",
         "Intermediate answer: George Washington.\n",
         "Final answer: When Mozart died George Washington was the president of the USA.\n",
         "\n",
-        "Question: Where did the Emperor of Japan, who ruled the year Maria Skłodowska was born, die?\"\"\"\n",
+        "Question: When did the Emperor of Japan, who ruled the year Maria Skłodowska was born, die?\"\"\"\n",
         "model = genai.GenerativeModel(model_name='gemini-1.5-flash-latest')\n",
         "Markdown(model.generate_content(prompt).text)"
       ]