Pull in updates from clenemt/docdash

[JoshuaKGoldberg]

Filing mochajs/mocha#5072 here. This package is a fork of the https://github.com/clenemt/docdash JSDoc 3 theme. Right now it's "54 commits ahead of, 89 commits behind clenemt/docdash:master".

The theme seems to be working fine but has a dependency on taffydb flagged by mochajs/mocha#5070. We should pull in upstream updates to the fork so that the latest clenemt/docdash fixes+features are available.

I suppose un-forking is theoretically doable too, but it seems like there are a lot of customizations on the Mocha side.