Fix typos and grammar in index.md

[dev-araujo]

Fix: Improve Portuguese Translation

Description
Corrected minor typos and formatting inconsistencies.

Fix: Corrected Benefícios(Benefits) to Desvantagens(Drawbacks)
Fix: Corrected rápido(quick) to rapidamente (Quickly)

Related Issue

[netlify]

✅ Deploy Preview for ethereumorg ready!

Name	Link
🔨 Latest commit	ec1ffe9
🔍 Latest deploy log	https://app.netlify.com/sites/ethereumorg/deploys/678f94a880b01b00084435fb
😎 Deploy Preview	https://deploy-preview-14719--ethereumorg.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.
Lighthouse	7 paths audited Performance: 51 (🟢 up 3 from production) Accessibility: 92 (no change from production) Best Practices: 89 (🔴 down 9 from production) SEO: 98 (no change from production) PWA: 59 (no change from production) View the detailed breakdown and full score reports

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[corwintines]

@lukassim could you bring these in to crowdin as well?

[gitpoap-bot]

Congrats, your important contribution to this open-source project has earned you a GitPOAP!

GitPOAP: 2025 Ethereum.org Contributor:

Join the [ethereum.org Discord server](https://ethereum.org/discord) to explore more ways to contribute to the project. Depending on the tasks you complete, you may also unlock additional rewards. Visit [ethereum.org/contributing](https://ethereum.org/contributing) to learn more.

Head to gitpoap.io & connect your GitHub account to mint!Keep buidling, keep learning, and let's grow the Ethereum open-source community together 🌱

Learn more about GitPOAPs here.

[lukassim]

@lukassim could you bring these in to crowdin as well?

Thanks, fixed in Crowdin