Undo and redo support

[frozen-lemonade[bot]]

Undo/redo support would be nice w/ their respective shortcuts. If I delete a class and want to readd it to my schedule, I'd like to be able to use command z instead of having to re-find + add it

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This issue was migrated from the old feedback system. Issue date: 11/2/2022, 5:17:57 PM