Better rsqrt

N.B.: The accuracy benefits of this is negligible at best, so don't expect anything big to happen. This is created
purely because I want to, and I can.

Tested to work every version since 1.14 (v1.0.1)

Replaces the constant Minecraft uses in their fast reciprocal square root
(also known as InvSqrt or rsqrt) functions, to yield better accuracy:

| Function | Original Value | More Accurate™ Value |
|----------|----------------|---------------------|
|fastInverseSqrt(float)| 0x5f3759df | 0x5f375a86|
|fastInverseSqrt(double)| 0x5fe6eb50c7b537aa | 0x5fe6eb50c7b537a9|

Since Minecraft only use these functions in rendering, this "fix" should not affect world generation or other functions
that rely on the vanilla result to yield expected results.

References

Both accessed on June 13th, 2021:

• Lomont, C. (2003). Fast Inverse Square Root
• Robertson, M. (2012). A Brief History of InvSqrt