Function fixed_sqrt 

fn fixed_sqrt(value: Fixed) -> Fixed

The square root of value, by the method FreeType uses.

Zero for anything that is not positive, so a caller never sees an imaginary answer.

https://gitlab.freedesktop.org/freetype/freetype/-/blob/80a507a6b8e3d2906ad2c8ba69329bd2fb2a85ef/src/psaux/psintrp.c#L1420