Update tutorial comments in class GenerativeModel (#116)

* Update comments in class GenerativeModel

* typo

---------

Co-authored-by: Mark Daoust <[email protected]>

Author: YebowenHu

google/generativeai/generative_models.py

@@ -122,15 +122,15 @@ class GenerativeModel:
     >>> genai.configure(api_key='YOUR_API_KEY')
     >>> model = genai.GenerativeModel('models/gemini-pro')
     >>> result = model.generate_content('Tell me a story about a magic backpack')
-    >>> response.text
+    >>> result.text
     "In the quaint little town of Lakeside, there lived a young girl named Lily..."
 
     Multimodal input:
 
     >>> model = genai.GenerativeModel('models/gemini-pro')
     >>> result = model.generate_content([
     ...     "Give me a recipe for these:", PIL.Image.open('scones.jpeg')])
-    >>> response.text
+    >>> result.text
     "**Blueberry Scones** ..."
 
     Multi-turn conversation: