[ES|QL] Update ES|QL inline docs for 8.14 (#180599)

- [x] rename AUTO_BUCKET to BUCKET

- [x] [Index
options](https://www.elastic.co/guide/en/elasticsearch/reference/master/esql-index-options.html)
- [ ] TODO update docs link to target current once branch has been cut
- [x]
[`SIGNUM`](https://www.elastic.co/guide/en/elasticsearch/reference/master/esql-functions-operators.html#esql-signum)
- [x] spatial functions
- [x]
[`ST_CENTROID_AGG`](https://www.elastic.co/guide/en/elasticsearch/reference/master/esql-functions-operators.html#esql-agg-st-centroid)
- [x]
[`ST_CONTAINS`](https://www.elastic.co/guide/en/elasticsearch/reference/master/esql-functions-operators.html#esql-st_contains)
- [x]
[`ST_DISJOINT`](https://www.elastic.co/guide/en/elasticsearch/reference/master/esql-functions-operators.html#esql-st_disjoint)
- [x]
[`ST_INTERSECTS`](https://www.elastic.co/guide/en/elasticsearch/reference/master/esql-functions-operators.html#esql-st_intersects)
- [x]
[`ST_WITHIN`](https://www.elastic.co/guide/en/elasticsearch/reference/master/esql-functions-operators.html#esql-st_within)
- [x]
[`ST_X`](https://www.elastic.co/guide/en/elasticsearch/reference/master/esql-functions-operators.html#esql-st_x)
- [x]
[`ST_Y`](https://www.elastic.co/guide/en/elasticsearch/reference/master/esql-functions-operators.html#esql-st_y)
- [x]
[`MV_SORT`](https://www.elastic.co/guide/en/elasticsearch/reference/master/esql-functions-operators.html#esql-mv_sort)
- [x]
[`MV_SLICE`](https://www.elastic.co/guide/en/elasticsearch/reference/master/esql-functions-operators.html#esql-mv_slice)
- [x]
[`MV_ZIP`](https://www.elastic.co/guide/en/elasticsearch/reference/master/esql-functions-operators.html#esql-mv_zip)
- [x]
[`VALUES`](https://www.elastic.co/guide/en/elasticsearch/reference/master/esql-functions-operators.html#esql-agg-values)

## Updates not necessarily linked to 8.14

- [x] Binary operators (ensure all up to date)