n-st created a pull request in webrender/trello-collapse-lists

Subtle toggle icon

*Part of a set of PRs: subtle icons #3, autohiding #4, or both #5.* I found the default black-on-white-circle toggle icon a bit too intrusive (my intent behind collapsing lists is having less clutter, after all), so here's a patch that replaces them with a more subtle backgroundless triangle: ![subtle-icon](https://user-images.githubusercontent.com/2692085/53489244-ff091e00-3a90-11e9-8d05-b3f866190c36.png)
02 27, 2019