Auto merge of #1151 - Anttonii:master, r=kvark
Auto merge of #1151 - Anttonii:master, r=kvark

Improved gfx_defines documentation

This is a draft. Currently looking for feedback on current information and possible improvements.

Closes #1135

tanderegg/gfx,davll/gfx,JohnColanduoni/gfx,JohnColanduoni/gfx,ColinKinloch/gfx,ColinKinloch/gfx,tanderegg/gfx,gfx-rs/gfx-rs