Merge changes from topic 'try-with-resource'

* changes:
  DiffCommand: Open DiffFormatter in try-with-resource
  DiffAlgorithms: Open Repository in try-with-resource
  DescribeCommandTest: Open FileWriter in try-with-resource
  CommitCommand: Open InputStream in try-with-resource
  DefaultNoteMerger: Open UnionInputStream in try-with-resource