Better/complete documentation of sys.stdin/stdout/stderr default behavior

See https://docs.python.org/3/library/sys.html?highlight=stdin#sys.stdin
The default behavior of sys.stdin/stdout/stderr is not fully documented (e.g. the default newline mode, depending on OS), and the current existing documentation is a lot more difficult to understand than it would need to be, referring to internal c-api settings instead of explaining in clear language what is going.

Given how important this information is and given that the behavior of sys.stdin/out/err is surprisingly DIFFERENT from what the default would be if open with default settings would be used, making the documentation more complete and easier to understand would be rather important. The number of questions on stackoverlow (partly with incorrect or hard to verify answers) about this is a good indicator of how confusing and important this matter is.

Comienza con la sección sobre sys.stdin, sys.stdout y sys.stderr de la página enlazada de documentación de Python y, a continuación, compara su descripción con el comportamiento de open con la configuración predeterminada en distintos sistemas operativos. El trabajo estará terminado cuando el comportamiento predeterminado de los saltos de línea y otras diferencias relevantes se expliquen de forma clara y precisa sin depender de terminología interna de la C API.