fx.collections: move fx_datetime to fx

fx/datetime.c

@@ -1,4 +1,4 @@
-#include <fx/collections/datetime.h>
+#include <fx/datetime.h>
 #include <fx/stream.h>
 #include <fx/string.h>
 #include <fx/value.h>
@@ -339,7 +339,7 @@ static enum fx_status encode_rfc3339(
 			dt->dt_sec);
 
 		if (dt->dt_msec > 0) {
-			fx_stream_write_fmt(out, NULL, ".%04ld", dt->dt_msec);
+			fx_stream_write_fmt(out, NULL, ".%03ld", dt->dt_msec);
 		}
 
 		if (!dt->dt_localtime) {
@@ -572,9 +572,8 @@ static fx_status _datetime_to_string(
 	fx_stream *out,
 	const char *format)
 {
-	struct fx_datetime_p *dt = fx_object_get_private(
-		obj->v_object,
-		FX_TYPE_DATETIME);
+	struct fx_datetime_p *dt
+		= fx_object_get_private(obj->v_object, FX_TYPE_DATETIME);
 
 	if (dt->dt_has_date) {
 		fx_stream_write_fmt(