DOC: Fix empty code block.

Change-Id: I908f3c2b3d67cf75fdd407505f7e31c783e43d54
DOC: Revise the registration examples of ITKSoftwareGuide

Change-Id: Ie7e981275a0bf5348eedaec02839adec4191c7f2
Merge topic 'book1-composite-example-empty-block'

3118c2f5 DOC: Fix empty code block.
Merge topic 'itkSftwrGuideRevision_r'

93a9533a DOC: Revise the registration examples of ITKSoftwareGuide