White is not identical to normal

This makes white work properly in white terminals when used for
`fish_color_*` variables. It's probably silly thing this small
mistake breaks, to be honest, but it's still a bug.

output.cpp

@@ -70,7 +70,7 @@ static const wchar_t *col[]=
     L"magenta",
     L"purple",
     L"cyan",
-    L"white"
+    L"white",
     L"normal"
 }
 ;