docs: fix incorrect docstring in AsyncAnthropicFoundry.models

[aryanmotgi]

Problem

In src/anthropic/lib/foundry.py, the AsyncAnthropicFoundry.models stub docstring still says "Azure Anthropic client", while its synchronous counterpart AnthropicFoundry.models correctly says "Anthropic Foundry client". This looks like a leftover from the rename of the Azure client to the Foundry client.

Evidence

src/anthropic/lib/foundry.py:366 (async):

def models(self) -> None:  # type: ignore[override]
    """Models endpoint is not supported for Azure Anthropic client."""

src/anthropic/lib/foundry.py:183 (sync, the correct phrasing):

def models(self) -> None:  # type: ignore[override]
    """Models endpoint is not supported for Anthropic Foundry client."""

All other "not supported" docstrings in this file consistently say "Anthropic Foundry client" — the async models stub is the only outlier.

Fix

Align the async docstring with the sync one so the user-facing wording is consistent and accurately refers to the Foundry client.

Why it's correct

• The class itself is AsyncAnthropicFoundry, not an Azure client.
• Every other stub in the file (batches, sync models, messages, beta) refers to the "Anthropic Foundry client".
• One-line, docs-only change — no behavioral or type impact.