Update: Add suggestions for no-unsafe-negation (fixes #12591)

[mdjermanovic]

What is the purpose of this pull request? (put an "X" next to item)

[X] Changes an existing rule #12591

What changes did you make? (Give an overview)

Suggestions for the no-unsafe-negation rule.

Example:

code: "!a in b",
errors: [{
  message: "Unexpected negating the left operand of 'in' operator.",
  suggestions: [
    {
      desc: "Negate 'in' expression instead of its left operand. This changes the current behavior.",
      output: "!(a in b)"
    },
    {
      desc: "Wrap negation in '()' to make the intention explicit. This preserves the current behavior.",
      output: "(!a) in b"
    }
}]

Is there anything you'd like reviewers to focus on?

Messages

[ilyavolodin]

Very nice change! I think this highlights power of suggestions when applied correctly.

[kaicataldo]

LGTM. Thanks for contributing!