Documentation improvements

[ricardoevvargas]

By creating this pull request, I confirm that I have read and fully accept and agree with one of the Petrobras' Contributor License Agreements (CLAs):

• ICLA: Individual Contributor License Agreement on behalf of only yourself;
• CCLA: Corporate Contributor License Agreement on behalf of your employer.

Our CLAs are based on the Apache Software Foundation's CLAs:

• ICLA: Individual Contributor License Agreement
• CCLA: Corporate Contributor License Agreement