cosmetic: sort value_t in types.h

toml/types.hpp

@@ -38,17 +38,17 @@ using table    = Table;
 
 enum class value_t : std::uint8_t
 {
+    Empty          = 0,
     Boolean        = 1,
     Integer        = 2,
     Float          = 3,
     String         = 4,
-    Datetime      = 5,
+    OffsetDatetime = 5,
     LocalDatetime  = 6,
     LocalDate      = 7,
     LocalTime      = 8,
     Array          = 9,
     Table          = 10,
-    Empty         = 0,
     Unknown        = 255,
 };