docs(pt-br): Overhaul and improve Portuguese translation

[VecchiR]

This commit addresses several issues in the Brazilian Portuguese (pt-br) documentation, moving away from ambiguous word-for-word translations and ensuring the document is fully translated and easier to understand.

• Improved Idiomatic Language: Many passages were rephrased to sound more natural in Portuguese, fixing weak or ambiguous sentences that resulted from a literal translation.
• Enhanced Code Example: The DiskStorage example now includes a more thorough explanation. This clarifies the purpose of the unique suffix for filename generation, which is a key concept that benefits from more detail for non-native English readers.
• Completed Translations: Finished translating parts of the document that were still in English, specially the limits table in the API section, and the 'Error handling' section (title and code comments).