Support high retraction speeds

[Xelinor]

Right now, if you do a retraction speed over 50mm/s it throws an error, but high flow hot ends today actually do as much as 100mm/s

[iFallUpHill]

Increased! https://github.com/iFallUpHill/flow-calculator/commit/9482cfbf13e1a7b35834e4e46f963d018bb674b1