rust-revlog: add invalidation detection to `NodeTree` class This will be useful for callers, such as `scmutil` who reuse a `NodeTree` instance as a cache. They would otherwise get hard errors if any mutation of the index occurred since instantiation. This is something the C index does not provide.

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edition = "2018"

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max_width = 79

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wrap_comments = true

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error_on_line_overflow = true