Support new eslint suggestions API

[wdoug]

Eslint has a new Suggestions API that was initially described in this RFC, and recently merged and released in eslint 6.7.0.

The suggestions API provides information for users to manually apply fixes for lint issues that don't have enough context to be auto-fixable. Here is an example of how it would work:

new RegExp("*\.js", "u")
//           ^^
//           ├ Remove the `\`. This maintains the current functionality. (no-useless-escape)
//           └ Replace the `\` with `\\` to include the actual backslash character. (no-useless-escape)

[kaste]

Hi! I thought the suggestions don't show up in the normal json report for the command line, t.i. only node based editors would get them.