Add support for inline uniform blocks

[Rua]

Changelog:

### Breaking changes
Changes to `DescriptorPool`:
- `DescriptorPool::new` now returns validation errors instead of panicking.
- `DescriptorPoolCreateInfo::can_free_descriptor_sets` has been replaced with a more generic `flags` field.

### Additions
- Added support for `InlineUniformBlock` descriptors.

Another nice-to-have feature, that was included in Vulkan 1.3. I also added backticks to all the code pieces in validation messages that were added in #2219, per Discord.

One important thing is still missing: the descriptor set allocator doesn't handle these descriptor types yet, it just asserts/panics. Descriptor pools have a new parameter, max_inline_uniform_block_bindings, but I don't know what the allocator should choose for that value. I can add it to this PR if there's an easy solution.

[marc0246]

Very nice, thanks! Don't worry about the descriptor set allocator for now, I'll fix it when I add StandardDescriptorSetAllocatorCreateInfo as planned (in a pretty obvious way). Note to self: add an example after that, as this is currently untested.