`VK_SHADER_STAGE_SUBPASS_SHADING_BIT_HUAWEI` is missing documentation, maybe also rename?

In the documentation of `VkShaderStageFlagBits`, a definition for `VK_SHADER_STAGE_SUBPASS_SHADING_BIT_HUAWEI` is missing. This would have been easy enough for me to fix directly in a PR, but I noticed that in `VkPipelineStageFlagBits2`, the older `VK_PIPELINE_STAGE_2_SUBPASS_SHADING_BIT_HUAWEI` is now replaced with `VK_PIPELINE_STAGE_2_SUBPASS_SHADER_BIT_HUAWEI`. Does this mean that for the shader stage, the name `VK_SHADER_STAGE_SUBPASS_BIT_HUAWEI` should also be introduced as a replacement?