a7dd4b5ab0 Add a rustdoc test to Denomination (Tobin C. Harding)
Pull request description:
Add a rustdoc test to the `Denomination` type to show basic usage.
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Kixunil:
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apoelstra:
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Tree-SHA512: 08f15c4641e70f043276b873e60fcf0e195fe50b6c5c18a245d2d609f4a4a4badc291aae1be532fc4890a91b2057cd308c86d0d3b85770b600a07499303a7bc4