type_descriptor: don't put auto-generaated type-registering statics into hidden namespace
type_descriptor: don't put auto-generaated type-registering statics into hidden namespace

Static global variables have internal linkage by default, so placing 'em
additionally into hidden namespace is not needed.
Also this little change enables placing types registering code into a
function.

uentity/blue-sky-re,uentity/blue-sky-re,uentity/blue-sky-re