Segmentations module: clicking on slider track should move slider in steps; spinner should increment last digit

[jamesobutler (James Butler)]

You can learn a little about CommitCheck from the post below or more directly at Style Guide — 3D Slicer documentation.

Commit message prefix

As discussed in this issue, the DOC: prefix is now valid when writing commit message. The Commit Style Guide and the commit check have both been updated. For reference, here is the regex used to validate the commit title: (BUG|COMP|DOC|ENH|PERF|STYLE)\: \w+