fix: remove trailing whitespace in docstring

- Remove trailing whitespace that was causing pre-commit formatting issues
- Ensure clean formatting for CI checks

Author: Wyn1996

tests/shared/test_streamable_http.py

@@ -1607,7 +1607,7 @@ async def bad_client():
 @pytest.mark.anyio
 async def test_client_unexpected_content_type_raises_mcp_error():
     """Test that unexpected content types raise McpError instead of just printing.
-    
+
     This test verifies that when a server returns HTML instead of MCP JSON,
     the client properly raises McpError wrapped in ExceptionGroup.
     """