DOC: Fix module description

Fix module description: remove hanging sentence part.

itk-module.cmake

@@ -1,7 +1,6 @@
 # Maintainer: Matt McCormick <matt.mccormick@kitware.com>
 set(DOCUMENTATION "This module contains a filter to compute higher order
 accurate numerical derivatives and gradients from an input scalar image.
-field from a displacement field image.
 Higher Order Accurate Derivative and Gradient Calculation in ITK
 https://www.insight-journal.org/browse/publication/775
 https://hdl.handle.net/10380/3231