Fix doctest unused variable warnings.

lib/arrays.ex

@@ -132,19 +132,19 @@ contents = quote do
       ##{@current_default_array}<[1, 2, 33, 4]>
       iex> arr = update_in(arr[1], (&(&1 * -2)))
       ##{@current_default_array}<[1, -4, 33, 4]>
-      iex> arr = update_in(arr[-1], (&(&1 + 1)))
+      iex> update_in(arr[-1], (&(&1 + 1)))
       ##{@current_default_array}<[1, -4, 33, 5]>
 
   Popping from a random location however, is not.
   Only removals of the last element of the array are fast.
   For this, use `Arrays.extract/1`.
 
       iex> arr = Arrays.new([1, -4, 33, 5])
-      iex> {33, arr} = pop_in(arr[-2])
+      iex> {33, _arr} = pop_in(arr[-2])
       ** (ArgumentError) There is no efficient implementation possible to remove an element from a random location in an array, so `Access.pop/2` (and returning `:pop` from `Access.get_and_update/3` ) are not supported by #{@current_default_array}. If you want to remove the last element, use `Arrays.extract/1`.
 
       iex> arr2 = Arrays.new([10, 20, 30])
-      iex> {20, arr2} = get_and_update_in(arr2[1], fn _ -> :pop end)
+      iex> {20, _arr2} = get_and_update_in(arr2[1], fn _ -> :pop end)
       ** (ArgumentError) There is no efficient implementation possible to remove an element from a random location in an array, so `Access.pop/2` (and returning `:pop` from `Access.get_and_update/3` ) are not supported by #{@current_default_array}. If you want to remove the last element, use `Arrays.extract/1`.
 
       iex> arr2 = Arrays.new([10, 20, 30])