Removes the `@timestamp` field mapping from several data stream index
template snippets.
With #59317, the `@timestamp` field defaults to a `date` field data type
for data streams.
This makes the data_stream timestamp field specification optional when
defining a composable template.
When there isn't one specified it will default to `@timestamp`.
(cherry picked from commit 5609353c5d164e15a636c22019c9c17fa98aac30)
Signed-off-by: Andrei Dan <andrei.dan@elastic.co>
Replaces `composable index template` and `composable template` with
`index template` throughout data stream-related docs.
`Composable index template` is only used to contrast with legacy index
templates.
With #58096, data streams now track the timestamp field mapping outside
of the template associated with the stream. This means you can no longer
update the timestamp field mapping using template changes.
This updates the associated data stream docs.
James Rodewig
Andrei Dan