Adapted better docstring

pystencils/gpu/indexing.py

@@ -129,7 +129,7 @@ class BlockIndexing(AbstractIndexing):
 
     Args:
         iteration_space: list of slices to determine start, stop and the step size for each coordinate
-        data_layout: tuple to determine the fast and slow coordinates.
+        data_layout: tuple specifying loop order with innermost loop last. This is the same format as returned by `Field.layout`.
         permute_block_size_dependent_on_layout: if True the block_size is permuted such that the fastest coordinate
                                                 gets the largest amount of threads
         compile_time_block_size: compile in concrete block size, otherwise the gpu variable 'blockDim' is used