ENH: Update the ToDo list of examples to import from Wiki.
ENH: Update the ToDo list of examples to import from Wiki.

Update the ITKWikiExamplesRepositoryImport.todo file with the ToDo list
corresponding to the examples in the wiki that are yet to be imported to
the Sphinx-based examples site.

Remove the WatershedImageFilter example from the list. Added in Change
22279.

Change-Id: I9f8a875f8fc4137f10c1deb887f18787dd18f3dc

InsightSoftwareConsortium/ITKExamples,InsightSoftwareConsortium/ITKExamples,InsightSoftwareConsortium/ITKExamples,InsightSoftwareConsortium/ITKExamples,InsightSoftwareConsortium/ITKExamples