doc change for time format (#315)

* doc change for time format

* add example

spiceaidocs/docs/reference/spicepod/datasets.md

@@ -132,11 +132,14 @@ Required to enable a retention policy on the dataset.
 ## `time_format`
 
 Optional. The format of the `time_column`. The following values are supported:
-
-- `unix_seconds` - Default. Unix timestamp in seconds.
-- `unix_millis` - Unix timestamp in milliseconds.
+- `timestamp` - Default. Timestamp without a timezone. E.g. `2016-06-22 19:10:25` with data type `timestamp`.
+- `timestamptz` - Timestamp with a timezone. E.g. `2016-06-22 19:10:25-07` with data type `timestamptz`.
+- `unix_seconds` - Unix timestamp in seconds. E.g. `1718756687`.
+- `unix_millis` - Unix timestamp in milliseconds. E.g. `1718756687000`.
 - `ISO8601` - [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) format.
 
+Spice emits a warning if the `time_column` from the data source is incompatible with the `time_format` config.
+
 :::warning[Limitations]
 
 - String-based columns are assumed to be ISO8601 format.