This was a workaround to be able to build on case-insensitive file
systems where it might get confused about <string.h> vs <String.h>.
Let's just not support building that way, so String.h can have an
objectively nicer name. :^)
This needs to be applied consistently in the rest of this UI, but here
is a start. I can't figure out what the right look should be right now
so I'm just gonna commit it this way and we'll work it out later. :^)
