[ban-ts-comment] require comment descriptions by default

[dimitropoulos]

now that #2099 is merged and users can specify allow-with-description for the comment directives specified in ban-ts-comment, this issue serves as a reminder to make this change for 4.0.

with the next major, we can consider setting the default to ts-expect-error: 'allow-with-comment'
@bradzacher 2020 05 25

Aside from the tests to be updated, the breaking change will look something like this:

const defaultOptions: Options = {
- 'ts-expect-error': true,
+ 'ts-expect-error': 'allow-with-description',
  'ts-ignore': true,
  'ts-nocheck': true,
- 'ts-check': false,
+ 'ts-check': 'allow-with-description',
  minimumDescriptionLength: 3,
};