add unsafeNegation to lint for in and instanceof

[macovedj]

I implemented the rule as eslint does without options. Happy to add other binary expressions if desired. Not sure if you want a PR per rule or not.

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[sebmck]

Sorry, one last thing. Could you add a small test here. Just another snapshot test that tests something basic. We can work on more test cases later. Thank you!

[macovedj]

@sebmck

Sorry, one last thing. Could you add a small test here. Just another snapshot test that tests something basic. We can work on more test cases later. Thank you!

Just took a look and my understanding is that the example string can get formatted if we want. Looks like eslint takes the stance that it's rare that anybody would want to negate the left operand, so if we decided to adopt the same philosophy, then this seems like an opportune time to implement it in generateJS in the lint api. They allow for ignoring though, and it seems like we'd only want to to that if rome allows ignoring, and I haven't come across that yet. Thoughts? Maybe I'm overcomplicating things and I could just push up something simple for now like you said.

[macovedj]

@sebmck You can probably disregard my earlier comment about tests. Just pushed a simple snapshot test.

[sebmck]

Looks good, thank you!