List.List' is deprecated:Fixed #191 for tim_sort.dart

[skdotv]

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Describe your change:

List.List' is deprecated: Fixed

• [ ] Fix a bug or typo in an existing algorithm?

Checklist:

• [x] I have read CONTRIBUTING.md.
• [x] This pull request is all my own work -- I have not plagiarized.
• [ ] I know that pull requests will not be merged if they fail the automated tests.
• [x] This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• [ ] All new Dart files are placed inside an existing directory.
• [ ] All new algorithms have a URL in its comments that points to Wikipedia or other similar explanation.
• [ ] If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.