Same thing though the wording is a little odd here and there. The diagram says it all - it is simply a solution of two vectors. As the airspeed increases the AoA decreases - if you extrapolate that line it eventually crosses into zero and then to negative pitch. That is outrunning the prop, and all of us have likely seen that on sport jobs with 4, 5 or 6" pitch props WOT straight down. It is used to good effect on some types of aerobatic aircraft, you can create somewhat of a "wall" with big blades and fine pitch.

Remember that airfoils have an ideal angle of attack, the angle or the small range of angles where they work most efficiently (best l/d), and it is easy to see why there is a process involved in homing in on the best prop for any particular engine and aircraft setup. It is the prop that pulls the aircraft to an airspeed where the working AoA is in the sweet spot of the blade design to get best efficiency from the prop, while absorbing all the power the engine has to offer. Intuitively, the prop blades have to be smaller to absorb the same power as a lower pitch setup with larger blades. There is no runaway situation, the aircraft's drag is constantly increasing as the square of the airspeed increase. The system reaches a limit - but the better the prop choie, the higher that limit within the bounds determined by available horsepower, drag, and the reality of never-perfect efficiency.

MJD