Given that the main goal of a question is to obtain the solution to what the question is specifically asking for, we should focus our answers on just that: keep orthographic and grammatical corrections as edits to the question, and avoid placing those in the answer. Future visitors will thank you for this, as they will find clean questions and answers to what they were looking for without being mixed with secondary issues.
Some people might think it sounds uninviting, but not at all. Those who edit (or suggest edits to) the question can still comment on those issues if really necessary. Otherwise, adding an edit with a summary of the changes made and leaving a small remark of "I have corrected your Portuguese, please check the question's edit history" will suffice. If they did not understand the correction, they may do one of three things:
- Research and (maybe) ask a new question.
- In small cases, reply to that correction with a comment in the question.
- Send the discussion to chat, requesting the corrector to participate.
[Portuguese version will be written by request.]