Update hdf5.md (#412)

Use the current syntax to collect ranges in the doc page

doc/hdf5.md

@@ -293,7 +293,7 @@ where dims is a tuple of integers.  For example
 ```julia
 b = d_create(fid, "b", Int, ((1000,),(-1,)), "chunk", (100,)) #-1 is equivalent to typemax(Hsize)
 set_dims!(b, (10000,))
-b[1:10000] = [1:10000]
+b[1:10000] = collect(1:10000)
 ```
 when dimensions are reduced, the truncated data is lost.  A maximum dimension of -1 is often referred to as unlimited dimensions, though it is limited by the maximum size of an unsigned integer.