Extending the section about function calling

[devayani-kv]

[Outline] I would like to add to the existing section about function calling. I plan to add the below points/topics:

• Give the reader a good idea of what exactly function calling is
• The parameters that one needs to take care while using function calling
• Code examples of function calling, using both closed source and opensource models

[mcharytoniuk]

@devayani-kv Sorry for the late response. I didn't get a notification from GitHub and didn't notice your issue.

As with your other ideas, I like this one! I think it will be a great fit.