If a tslint.json doesn't extend from tslint-config-prettier, recommend Prettier

[JoshuaKGoldberg]

😄. TSLint maintainers (myself included) have been recommending moving off of whitespace rules for quite some time now. I believe ESLint maintainers are of the same opinion, though it'd be nice to have a source on that.

[JoshuaKGoldberg]

Well this is unfortunate. tslint --print-config doesn't print anything under extends: just an empty array. I'll file an issue on TSLint to talk about improving this.

[JoshuaKGoldberg]

#348 confirmed this is at least an acceptable opinion for the TSLint and typescript-eslint side. Hooray!