chore: add comment

Author: ovr

rust/cubesql/pg-srv/src/values/timestamp.rs

@@ -107,6 +107,8 @@ impl ToProtocolValue for TimestampValue {
             None => self.to_naive_datetime(),
             Some(_) => self.to_fixed_datetime()?.naive_utc(),
         };
+
+        // 2022-04-25 15:36:49.39705+00
         let as_str = ndt.format("%Y-%m-%d %H:%M:%S%.6f").to_string();
 
         match self.tz_ref() {