docs: improve sentiments example model compatibility

[njhale]

Description

Re-engineer the sentiments.gpt example tool body prompt wording so that it works with claude-3-opus and gemini-1.5.

Notes

• The existing prompt is useful in identifying the shortcomings of these LLMs, so it may be useful to keep around in some capacity.
• claude-3-opus is interesting because it, along with gpt-4-turbo and gpt-4o, are capable of inferring the necessary sequence of chained tool calls and come to the correct result with a prompt as basic as Get the sentiments of the tweet at ${url}.. For that same basic prompt, gemini-1.5 fails to chain functions at all and just immediately calls sentiments with hallucinated text.