* Bump API patch number and header version number to 15 for this
update.
Github Issues:
* Fixed the <<glossary,Glossary>> entry for Fragment Input Attachment
Interface to specify code:UniformConstant storage class (public issue
156).
* Disallow lazily allocated memory for buffers in the description of
slink:VkMemoryRequirements::pname:memoryTypeBits (public issue 196).
* Add numbered figure captions (public issue 219).
* Fix output variable names in the <<fundamentals-fpfixedconv,Conversion
from Floating-Point to Normalized Fixed-Point>> section and related
minor normative language and markup cleanup (public issue 220).
Internal Issues:
* Fix reference to nonexistent etext:VK_IMAGE_LAYOUT_TRANSFER_{SRC,DST}BIT
to the actual etext:VK_IMAGE_LAYOUT{SRC,DST}_OPTIMAL (internal issue
296).
* Update the <<sparsememory-sparse-memory-aliasing,Sparse Resource
Implementation Guidelines>> to refer to the correct feature names
(internal issue 305).
