Agent Input Clarity and Documentation

[isaacmichaud]

This is not exactly a simple problem to fix, but the BaseAgent class and all the other Agents generally define the _invoke method with its first positional argument as inputs: Mapping[str, Any]. I think the class of inputs is suppose to be is the respective agent's state TypeDict. If a user tries to invoke an agent with an incorrectly specified state then it is likely that an error will be thrown somewhere in the code. Because the documentation doesn't say what the required fields are to specify a valid state for each agent, the user is left debugging it by trial and error.

Also, the automated API documentation is not up to date compared to some of our examples.