Add first devtool: prev/next arrows for broken swiping in Chrome

@incuna/js Please merge, ta!
I'm not in disagreement, but I'd like the ease-of-use to remain. Requiring both `edetail-devtools` and `Cocktail` to run this is too much I think. It would be nice to keep it as just `edetail-devtools` and give it what you are working with.