Add version display for associated consts Fixes #54030. <img width="1440" alt="screenshot 2018-11-08 at 23 57 29" src="https://user-images.githubusercontent.com/3050060/48232648-99decf00-e3b2-11e8-9f41-6bd12a161c7d.png"> r? @QuietMisdreavus
For more information about how librustdoc
works, see the rustc guide.