Remove consistent-output from recommended in future major version?

[bmish]

We had some previous discussion about this in #258 but I want to move the discussion here and decide if we should remove consistent-output from the recommended config in a future major version.

My thoughts:

• The rule isn't as necessary anymore since ESLint v7 validates that test cases provide output when they produce an autofix
• It's tedious to include output: null when not necessary
• Since this rule doesn't autofix, users may end up turning it off rather than manually fix dozens violations, or be scared away from using the plugin entirely
• To be clear, I'm definitely in favor of rules that can catch issues early even when ESLint itself would also catch the issues. This rule can be helpful in this regard, but "consistency" is an imperfect heuristic. Just because some test cases for a rule have an autofix doesn't mean that all the rule's test cases do, which is why I think it can sometimes be tedious how this rule requires specifying output: null for the non-fixable test cases even though that's already the implicit behavior