Function matmul_forward 

pub fn matmul_forward<T: Triton, D: Num, const BLOCK_M: i32, const BLOCK_N: i32, const BLOCK_K: i32, const GROUP_M: i32>(
    a_ptr: T::Pointer<D>,
    b_ptr: T::Pointer<D>,
    c_ptr: T::Pointer<D>,
    M: i32,
    N: i32,
    K: i32,
)

Forward: C = A @ B