[v11.0.x] Document Unix ms format for time type parsing (#89416)

Co-authored-by: Jack Baldry <jack.baldry@grafana.com>
Co-authored-by: Isabel Matwawana <76437239+imatwawana@users.noreply.github.com>
Co-authored-by: Oleg Zaytsev <mail@olegzaytsev.com>

docs/sources/panels-visualizations/query-transform-data/transform-data/index.md

@@ -298,6 +298,9 @@ This transformation has the following options:
   - **Numeric** - attempts to make the values numbers
   - **String** - will make the values strings
   - **Time** - attempts to parse the values as time
+    - The input will be parsed according to the [Moment.js parsing format](https://momentjs.com/docs/#/parsing/)
+    - It will parse the numeric input as a Unix epoch timestamp in milliseconds.
+      You must multiply your input by 1000 if it's in seconds.
     - Will show an option to specify a DateFormat as input by a string like yyyy-mm-dd or DD MM YYYY hh:mm:ss
   - **Boolean** - will make the values booleans
   - **Enum** - will make the values enums