Remove enforcement rules of rule F.17

Rule F.17 (For “in-out” parameters, pass by reference to non-const) and Con.3 (By default, pass pointers and references to consts) have both two enforcement rules of which one of them is nearly identical:

• F.17: Warn about functions regarding reference to non-const parameters that do not write to them
• Con.3 Flag a function that does not modify an object passed by pointer or reference to non-const

This means that 2 rules will fire if a non-const reference parameter is not changed in the corresponding function body. Having 2 rules firing for the same situation is a coding standard design smell.

In order to solve this, I suggest to remove all enforcements from rule F.17 because the rule is about expresssing an intention, i.e. an in-out parameter. That is something you can't check automatically. To take this one step further, one might even consider to remove F.17 completely because we also have rule F.20 (For “out” output values, prefer return values to output parameters). Since F.20 describes some exceptions, removing F.17 might a bit too strong. So I suggest to remove the 2 enforcement rules of rule F.17.

Start by locating the F.17 and Con.3 guideline sections and comparing their enforcement rules. Remove both F.17 enforcement rules while preserving the guidance and the stated exceptions in F.20; check the surrounding document for consistent formatting and references.