turnip: Use Vulkan 1.1 names instead of KHR

turnip: Use Vulkan 1.1 names instead of KHR

That is, drop KHR from all tokens that were promoted to Vulkan 1.1.
The consistency makes ctags more useful (it now jumps directly to the
real definitions in vulkan_core.h instead of the typedefs); and it makes
the code slightly less verbose.