Panic when max history is set to 0

[Volkalex28]

If set the maximum amount of history to 0, then according to the documentation, undo / redo should be disabled. Actually there is a panic at change of the text in TextArea. This is because the value in history.rs:115 is out of range. I consider it necessary to add an additional condition for checking compliance with the boundaries

[rhysd]

Thanks for reporting this. I'll take a look.