For the FixedArray type, generate more appropriate C# code

[szhang21]

This issue was discovered in Magicphysx. Here is the original Rust code and the currently generated C# code, it does not ensure the consistency of the struct's memory layout.

#[derive(Clone, Copy)]
#[cfg_attr(feature = "debug-structs", derive(Debug))]
#[repr(C)]
pub struct PxContactModifyPair {
    pub actor: [*const PxRigidActor; 2],
    pub shape: [*const PxShape; 2],
    pub transform: [PxTransform; 2],
    pub contacts: PxContactSet,
}

[StructLayout(LayoutKind.Sequential)]
public unsafe partial struct PxContactModifyPair
{
    public fixed byte/* PxRigidActor, this length is invalid so must keep pointer and can't edit from C# */ actor[2];
    public fixed byte/* PxShape, this length is invalid so must keep pointer and can't edit from C# */ shape[2];
    public fixed byte/* PxTransform, this length is invalid so must keep pointer and can't edit from C# */ transform[2];
    public PxContactSet contacts;
}

I believe the following generated code would be more appropriate.

[StructLayout(LayoutKind.Sequential)]
public unsafe partial struct PxContactModifyPair
{
    public PxRigidActor* actor1;
    public PxRigidActor* actor2;
    public PxShape* shape1;
    public PxShape* shape2;
    public PxTransform transform1;
    public PxTransform transform2;
    public PxContactSet contacts;
}

[szhang21]

In this case, if we directly pass the C# struct to native code, it will also produce the correct result and we can directly operate on the members of the returned structure from native.