LLMObs annotationContext params are incorrect

[dylanmoz]

Documentation Page

https://docs.datadoghq.com/llm_observability/instrumentation/sdk/?tab=nodejs#annotating-auto-instrumented-spans

Issue Description

The document arguments do not include the prompt field.

Under prompt tracking, the field is included in the example, but the shape is incorrect, chat_template is not a allowed field

https://docs.datadoghq.com/llm_observability/instrumentation/sdk/?tab=nodejs#prompt-tracking

https://github.com/DataDog/dd-trace-js/blob/7dad226373cb171e896418dd0f5ca55df312fc3f/index.d.ts#L3356

Also, the link to hallucination doesn't go to a specific anchor: https://docs.datadoghq.com/llm_observability/evaluations/managed_evaluations/?tab=openai#hallucination

@urseberry