Fix typo (#2382)

Co-authored-by: Joe Hamman <joe@earthmover.io>

src/zarr/core/sync.py

@@ -133,7 +133,7 @@ def sync(
 
     finished, unfinished = wait([future], return_when=asyncio.ALL_COMPLETED, timeout=timeout)
     if len(unfinished) > 0:
-        raise TimeoutError(f"Coroutine {coro} failed to finish in within {timeout} s")
+        raise TimeoutError(f"Coroutine {coro} failed to finish within {timeout} s")
     assert len(finished) == 1
     return_result = next(iter(finished)).result()