Function log_softmax_forward 

pub fn log_softmax_forward<T: Triton, const BLOCK_SIZE: i32>(
    x_ptr: T::Pointer<f32>,
    y_ptr: T::Pointer<f32>,
    _n_rows: i32,
    n_cols: i32,
)
where
    T::I32Tensor: Tensor<i32, 1> + Comparison<i32, BoolTensor = T::BoolTensor>,
    T::Pointer<f32>: AddOffsets<i32, 1, T::I32Tensor, Output = T::Tensor<T::Pointer<f32>>>,

Forward: y = x - log(sum(exp(x))) [numerically stable: subtract max first]