Fix FLOWSPEC vs QOS confusion.

[MarekKnapek]

The current documentation is talking about the QOS parameter in introduction summary, but about the FLOWSPEC parameter later on in place where the parameter is described, this is confusing. But the header files are talking about the QOS parameter. Upon further inspection the documentation is talking about the pointer pointing to two consecutive FLOWSPEC parameters followed by single user data parameter. Guess what, the QOS structure is exactly that. Thus, by accepting the change proposed in this PR, the documentation will be in sync with the header files. And the documentation will be more correct, more consistent, more useful and less confusing for the end user.

[prmerger-automator]

@MarekKnapek : Thanks for your contribution! The author(s) have been notified to review your proposed change.