Make parallel_evaluation_example more robust (#1861)

Author: DouweM

docs/evals.md

@@ -333,16 +333,16 @@ dataset = Dataset(
 
 
 async def double_number(input_value: int) -> int:
-    """Function that simulates work by sleeping for a second before returning double the input."""
+    """Function that simulates work by sleeping for a tenth of a second before returning double the input."""
     await asyncio.sleep(0.1)  # Simulate work
     return input_value * 2
 
 
 # Run evaluation with unlimited concurrency
 t0 = time.time()
 report_default = dataset.evaluate_sync(double_number)
-print(f'Evaluation took less than 0.3s: {time.time() - t0 < 0.3}')
-#> Evaluation took less than 0.3s: True
+print(f'Evaluation took less than 0.5s: {time.time() - t0 < 0.5}')
+#> Evaluation took less than 0.5s: True
 
 report_default.print(include_input=True, include_output=True, include_durations=False)  # (1)!
 """