feat(linter): overhaul unicorn/no-useless-spread

[DonIsaac]

I got tired of seeing useless spreads on ternaries and arr.reduce() within my company's internal codebase so I overhauled this rule.

Changes

• add fixer for object spreads

  const before = { a, ...{ b, c }, d }
  const after = { a,  b, c, d } // fixer does not dedupe spaces before `b`

• recursively check for useless clones on complex expressions. This rule now catches and auto-fixes the following cases:

  // ternaries when both branches create a new array or object
  const obj = { ...(foo ? { a: 1 } : { b: 2 }) }
  // recursive, so this can support complex cases
  const arr = [ ...(foo ? a.map(fn) : bar ? Array.from(iter) : await Promise.all(bar)) ]
  // reduce functions where the initial accumulator creates a new object or array
  const obj = { ...(arr.reduce(fn, {}) }

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[codspeed-hq]

CodSpeed Performance Report

Merging #4791 will not alter performance

_{Comparing don/linter/feat/no_useless_spread_overhaul (b3c3125) with main (5992b75)}

Summary

✅ 29 untouched benchmarks

[graphite-app]

Merge activity

• Aug 10, 12:49 AM EDT: The merge label 'merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
• Aug 10, 12:49 AM EDT: Boshen added this pull request to the Graphite merge queue.
• Aug 10, 12:53 AM EDT: Boshen merged this pull request with the Graphite merge queue.