fix(theme-translations): Add missing Portuguese (pt-BR) theme translations and improve some of it.

[marcelocell]

Pre-flight checklist

• I have read the Contributing Guidelines on pull requests.
• If this is a code change: I have written unit tests and/or added dogfooding pages to fully verify the new behavior.
• If this is a new API or substantial change: the PR has an accompanying issue (closes #0000) and the maintainers have approved on my working plan.

Motivation

Complete pt-BR translation.

Test Plan

Test links

Deploy preview: https://deploy-preview-11315--docusaurus-2.netlify.app/

Related issues/PRs

[netlify]

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[github-actions]

⚡️ Lighthouse report for the deploy preview of this PR

URL	Performance	Accessibility	Best Practices	SEO	Report
/	🔴 47	🟢 98	🟢 100	🟢 100	Report
/docs/installation	🟠 59	🟢 97	🟢 100	🟢 100	Report
/docs/category/getting-started	🟠 68	🟢 100	🟢 100	🟠 86	Report
/blog	🟠 59	🟢 96	🟢 100	🟠 86	Report
/blog/preparing-your-site-for-docusaurus-v3	🟠 57	🟢 92	🟢 100	🟢 100	Report
/blog/tags/release	🟠 59	🟢 96	🟢 100	🟠 86	Report
/blog/tags	🟠 65	🟢 100	🟢 100	🟠 86	Report

[slorber]

Thanks 👍

I can't really review 😅 but at least you signed the CLA unlike the other PR (#11167)