feat(jsx-key): check for array related method calls with jsx elements/fragments

[SimonSchick]

WIP, pending initial feedback, slightly worried this check may be overly broad.

Things to add:

• Setting to make this behavior opt-in unless we want it to be the default.
• Optimization of esquery usage? Seems potentially very wasteful.
• Check methods for exhaustiveness, there (fill, toSpliced) being more exotic candidates

Fixes #3937

[ljharb]

I'm not sure it's a good idea to assume any method named "push" or "splice" is happening on an array, unless it's a TS codebase.

[SimonSchick]

That was kinda my thinking too but I'm unsure how much better we can do without types.

I thought about trying to trace the symbol we are pushing to and see if it is a array declaration but that feels very much like a hack.

On the other hand I'd assume push, unshift and concat are the most commonly used methods for this anti-pattern and these are not exactly common method names in in relation to jsx usage so false positives should be extremely rare.

Question it if it is rare enough to proceed with this vague targetting strategy?

I did some rough searching via https://github.com/search?type=code&q=%28path%3A*.tsx+OR+path%3A*.jsx%29+%2F.%2B%5C.push%5C%28%3C.%2B%5C%29%3B%2F and found nothing that stands out, had to vary the search query a fair bit since github code search seems to limit results to 100 for some reason.

[ljharb]

concat exists on a number of things, and i agree false positives will be rare, but nonzero is nonzero.

Adding this change under an option is smart if it has a nonzero risk of false positives, though.

[SimonSchick]

I'll add an option then, and also fix the failing tests for legacy versions (I really wish those get pruned 😢 ).