Found in 2 comments on Hacker News
chadrs · 2020-09-15 · Original thread
At the string literal level doesn't do anything, but the standard library adds an extension method to string called `stripMargin`. This has some nice examples https://www.oreilly.com/library/view/scala-cookbook/97814493...
ohmygeek · 2017-03-27 · Original thread
Scala Cookbook: http://shop.oreilly.com/product/0636920026914.do (most of it is available online here: http://scalacookbook.com/)

Once you are done with this, you can pretty much pick any of the projects here and start reading the source code:

https://github.com/lauris/awesome-scala https://github.com/adamw/awesome-scala

Reading code is the probably the best way to learn any programming language IMO