perf: apply optional chaining and an arguments->args change

[JoshuaKGoldberg]

👋 hi! I just learned about this repo's performance challenge. Very fun. It's pretty optimized as-it-is, so most things I tried didn't result in any positive impact in goober.modern.js after gzipping locally.

But, I did find two changes that each showed small improvements locally:

• In the wrapper function within styled.js, switching the let _args = arguments to a modern ...args rest (thereby also changing the function to an => arrow lambda)
• Using ?. optional chaining as syntax sugar in dist/goober.modern.js whenever possible, as optional chaining is supported in modern environments per caniuse's optional chaining query and kangax's optional chaining row

Files created by running:

1. npm run build
2. gzip dist/goober.modern.js --best

Measurements taken by opening Get Info on Mac.

Change(s)	goober.modern.js	goober.modern.js.gz	.gz Δ (bytes)
(baseline)	2,284 bytes	1,269 bytes	(n/a)
Just _args	2,261 bytes	1,263 bytes	-6 🟢
Just ?.	2,269 bytes	1,263 bytes	-6 🟢
_args and ?.	2,250 bytes	1,260 bytes	-9 🟢

---

Note: Optional chaining is implemented right now with typescript-eslint's @typescript-eslint/prefer-optional-chain. Which is a very silly, over-the-top way to get this to work... but all the alternatives I'd tried didn't work!

• I tried using optional chaining in src/ files and adding '@babel/plugin-syntax-logical-assignment-operators' to babel.config.cjs, but even after updating to the latest @babel/* packages, it kept transpiling down to null==... checks in dist/
• Failing that, I'd have preferred to use a more direct tool such as https://github.com/villesau/optional-chaining-codemod, but it misses a g && g() in the output (blocked on some.object && some.object.fn() and this.object && this.object.value not handled villesau/optional-chaining-codemod#51)

If you know a way to get optional chaining to work in an output bundle without installing four dev dependencies, please let me know!

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Name	Status	Preview	Comments	Updated (UTC)
goober-rocks	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Aug 13, 2023 4:21am

[JoshuaKGoldberg]

Ping @cristianbote, is the challenge still active? I enjoyed this PR, but it did take some time to get to. If this repo isn't active anymore I'd think it'd be best to make that clear.