Logical and grammatical error in prompt_llm_parser.ipynb (shorthills…

…-ai#95)

* Update modal.py

feat: Raise KeyError when 'prompt' key is missing in JSON response

This commit updates the error handling in the code to raise a KeyError when
the 'prompt' key is not found in the JSON response. This change makes the code
more explicit about the nature of the error, helping to improve clarity and
debugging.

* prompt_llm_parser.ipynb

---------

Co-authored-by: Aashish Saini <141953346+ShorthillsAI@users.noreply.github.com>

docs/docs/expression_language/cookbook/prompt_llm_parser.ipynb

@@ -30,7 +30,7 @@
    "source": [
     "## PromptTemplate + LLM\n",
     "\n",
-    "The simplest composition is just combining a prompt and model to create a chain that takes user input, adds it to a prompt, passes it to a model, and returns the raw model output.\n",
+    "The simplest composition is just combing a prompt and model to create a chain that takes user input, adds it to a prompt, passes it to a model, and returns the raw model output.\n",
     "\n",
     "Note, you can mix and match PromptTemplate/ChatPromptTemplates and LLMs/ChatModels as you like here."
    ]