[swift-evolution] Case conventions for mixed-case words (like

[Justin Jia]

I think ipad and IPAD are better. Ipad and IPad look really bad. 
e.g isIPAD / ipadUser / isNAN / nan

Or what about this: For lowerCamelCase, we use all lower letters (like ipad).
For UpperCamelCase, we keep the original one (iPad). 
e.g. isiPad / ipadUser isNaN / nan

Justin