An error in the function FixedPointReflectionPhases

[vivienlonde]

Describe the bug
FixedPointReflectionPhases returns NaN phases.
https://github.com/microsoft/QuantumLibraries/blob/main/Standard/src/AmplitudeAmplification/StandardAlgorithms.qs#L53

Expected origin of the bug
At line 59: let beta = Cosh((1.0 / nQueriesDouble) * ArcCosh(Sqrt(successMin)));
ArcCosh is called on a value less than 1.

Expected fix
From https://arxiv.org/pdf/1409.3305.pdf: gamma^{-1} = T_{1/L} (1/delta).
I think that the Cosh and ArcCosh should be Cos and ArcCos instead.
(Other fixes may be needed too).

Additional context
Thanks for the great Amplitude Amplification library!