Ambiguity about integer format type

It is ambiguous to determine a type of a format. That is required e.g. for `vkCmdBlitImage`, which demands:

> Integer formats **can** only be converted to other **integer formats** with the same signedness.

`_USCALED` and `_SSCALED` sometimes seem to say they are integer formats:

> - `VK_FORMAT_R8_USCALED` specifies a one-component, 8-bit unsigned scaled integer format that has a single 8-bit R component.
> - `VK_FORMAT_R8_SSCALED` specifies a one-component, 8-bit signed scaled integer format that has a single 8-bit R component.

I think that is incorrect, as they are float formats (at least for the purposes of SPIR-V).

If they are integer formats (for the purposes of `vkCmdBlitImage`), then it is ambiguous whether `_UNORM` and `_SNORM` are integer formats too.