Auto merge of #2998 - simonsan:patch-1, r=jtgeibel
Auto merge of #2998 - simonsan:patch-1, r=jtgeibel

Added Accessibility category

I've added the `accessibility` category to cover crates that implement features for the convenience of disabled people.

I wanted to start a project that translates given colour codes to colours colorblind people can distinguish more easily, but I haven't found a category to fit it. What else belongs in this category could be crates that interoperate with peoples screenreaders, new screenreader implementations or other assistive technology.

rust-lang/crates.io,rust-lang/crates.io,rust-lang/crates.io,rust-lang/crates.io