Fix typo newly found by codespell (#1554)

docs/tutorial.rst

@@ -1315,7 +1315,7 @@ better performance, at least when using the Blosc compression library.
 
 The optimal chunk shape will depend on how you want to access the data. E.g.,
 for a 2-dimensional array, if you only ever take slices along the first
-dimension, then chunk across the second dimenson. If you know you want to chunk
+dimension, then chunk across the second dimension. If you know you want to chunk
 across an entire dimension you can use ``None`` or ``-1`` within the ``chunks``
 argument, e.g.::