feat(formatter): format @starting-style

[ematipico]

Summary

Adds formatting for @starting-style at rule.

Test Plan

Added a test case

[netlify]

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Lighthouse	1 paths audited Performance: 95 (🔴 down 5 from production) Accessibility: 97 (no change from production) Best Practices: 100 (no change from production) SEO: 93 (no change from production) PWA: - View the detailed breakdown and full score reports

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[codspeed-hq]

CodSpeed Performance Report

Merging #2213 will degrade performances by 6.39%

_{⚠️ No base runs were found}

_{Falling back to comparing feat/css-formatting-styles (6f93ec8) with main (62fbec8)}

Summary

❌ 1 regressions
✅ 92 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	main	feat/css-formatting-styles	Change
❌	big5-added.json[cached]	2.3 ms	2.4 ms	-6.39%