Compute shader chapter documentation not properly updated to timeline semaphores

[SaschaWillems]

The compute shader chapter code been updated to use Timeline semaphores. The documentation though hasn't been properly updated and still uses separate fences, e.g.:

We then use these to synchronize the compute buffer submission with the graphics submission:

[,c++]
----
{
    // Compute submission
    while ( vk::Result::eTimeout == device->waitForFences(**computeInFlightFences[frameIndex], vk::True, UINT64_MAX) )
        ;

    updateUniformBuffer(frameIndex);
    device->resetFences( **computeInFlightFences[frameIndex] );
    computeCommandBuffers[frameIndex]->reset();
    recordComputeCommandBuffer();

    const vk::SubmitInfo submitInfo({}, {}, {**computeCommandBuffers[frameIndex]}, { **computeFinishedSemaphores[frameIndex]});
    computeQueue->submit(submitInfo, **computeInFlightFences[frameIndex]);
}
{
    // Graphics submission
    while ( vk::Result::eTimeout == device->waitForFences(**inFlightFences[frameIndex], vk::True, UINT64_MAX))
...

    device->resetFences(  **inFlightFences[frameIndex] );
    commandBuffers[frameIndex]->reset();
    recordCommandBuffer(imageIndex);

    vk::Semaphore waitSemaphores[] = {**presentCompleteSemaphore[frameIndex], **computeFinishedSemaphores[frameIndex]};
    vk::PipelineStageFlags waitDestinationStageMask[] = { vk::PipelineStageFlagBits::eVertexInput, vk::PipelineStageFlagBits::eColorAttachmentOutput };
    const vk::SubmitInfo submitInfo( waitSemaphores, waitDestinationStageMask, {**commandBuffers[frameIndex]}, {**renderFinishedSemaphore[frameIndex]} );
    graphicsQueue->submit(submitInfo, **inFlightFences[frameIndex]);
----