Add info about InfluxQL GROUP BY time() with time bounds behavior in subqueries

Nobody has claimed this yet.

If you use `GROUP BY time()` in a subquery _and_ include time bounds in the `WHERE` clause, the `WHERE` clause has to be to be in the inner query before the `GROUP BY` clause, not the outer query. Otherwise the query returns no results.

For example, the following query doesn't return any results:

```sql
SELECT
mean("price") AS "mean_price"
FROM
(
SELECT
MEAN("price") AS "price"
FROM
"bitcoin".."coindesk"
GROUP BY
"code",
time(1d)
)
WHERE
time >= '2023-01-01T00:00:00Z'
AND time < '2023-02-01T00:00:00Z'
```

However, the following query does return results:

```sql
SELECT
mean("price") AS "mean_price"
FROM
(
SELECT
MEAN("price") AS "price"
FROM
"bitcoin".."coindesk"
WHERE
time > '2023-01-01T00:00:00Z'
AND time < '2023-02-01T00:00:00Z'
GROUP BY
"code",
time(1d)
)
```

##### Relevant URLs

- https://docs.influxdata.com/influxdb/v2/query-data/influxql/explore-data/subqueries/
- https://docs.influxdata.com/influxdb/cloud/query-data/influxql/explore-data/subqueries/

Start with the InfluxQL subqueries documentation at the linked InfluxDB URLs and compare the existing guidance with the two example queries in the issue. Document that time bounds must be placed in the inner query before GROUP BY time() for results to be returned, using the examples to show the differing behavior.

Written by the indexing model from the issue text.