update anthropic doc link (#6198)

haystack/nodes/prompt/invocation_layer/anthropic_claude.py

@@ -41,7 +41,7 @@ def __init__(self, api_key: str, model_name_or_path: str = "claude-2", max_lengt
  :param api_key: The Anthropic API key.
  :param kwargs: Additional keyword arguments passed to the underlying model. The list of Anthropic-relevant
  kwargs includes: stop_sequences, temperature, top_p, top_k, and stream. For more details about these kwargs,
- see Anthropic's [documentation](https://console.anthropic.com/docs/api/reference).
+ see Anthropic's [documentation](https://docs.anthropic.com/claude/reference/complete_post).
  """
  super().__init__(model_name_or_path)
  if not isinstance(api_key, str) or len(api_key) == 0: