fix: Update rules for new TS recommended

[itajaja]

it's on by default with ts eslint 3.0. wdygt?

[taion]

ref typescript-eslint/typescript-eslint#1423

we should remove the override for explicit-function-return-type, as that's no longer present (and that was what "broke")

we need to change ban-ts-ignore to ban-ts-comment

i wish we could make this check just for "arg type defs present", though. that would be useful; we often forget to do : Props. i guess no-implicit-any covers that, though.

[itajaja]

i guess no-implicit-any covers that, though.

right, that was my thinking