Useful missing DSL flags

[mihaisoloi]

When working with Scala 2.13 I find it very useful to have the following list enabled as well in DEV mode:

List(
      "-explaintypes", // Explain type errors in more detail.
      "-Vimplicits", // Enables the tek/splain features to make the compiler print implicit resolution chains when no implicit value can be found
      "-Vtype-diffs", // Enables the tek/splain features to turn type error messages (found: X, required: Y) into colored diffs between the two types
    )