Fix LLM terms

Updated all instances of mlm_client and mlm_model to llm_client and llm_model in the readme. The previous terms (mlm_client and mlm_model) are incorrect in the context of configuring Large Language Models (LLMs), as "MLM" typically refers to Masked Language Models, which is unrelated to the intended functionality. This change aligns the documentation with standard naming conventions for LLM configuration parameters and improves clarity for users integrating with LLMs like OpenAI's GPT models.

README.md

@@ -39,14 +39,14 @@ result = markitdown.convert("test.xlsx")
 print(result.text_content)
 ```
 
-You can also configure markitdown to use Large Language Models to describe images. To do so you must provide mlm_client and mlm_model parameters to MarkItDown object, according to your specific client.
+You can also configure markitdown to use Large Language Models to describe images. To do so you must provide llm_client and llm_model parameters to MarkItDown object, according to your specific client.
 
 ```python
 from markitdown import MarkItDown
 from openai import OpenAI
 
 client = OpenAI()
-md = MarkItDown(mlm_client=client, mlm_model="gpt-4o")
+md = MarkItDown(llm_client=client, llm_model="gpt-4o")
 result = md.convert("example.jpg")
 print(result.text_content)
 ```