layers: Update validation layer details doc
layers: Update validation layer details doc

Added new image test for undefined format in CreateRenderPass
attachment description and updated notes for missing tests.

Change-Id: I6a928213da8dc86d59a33a704cbbec8bd3cfbd45

elongbug/Vulkan-LoaderAndValidationLayers,elongbug/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers,elongbug/Vulkan-LoaderAndValidationLayers,elongbug/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers