[Docs] Kibana ES|QL updates (#224725)

This PR reproduces relevant changes from
elastic/docs-content#1818 for 9.1

Elasticsearch counterpart:
elastic/elasticsearch#129782

Author: florent-leborgne

docs/discover/try-esql.asciidoc

@@ -123,13 +123,4 @@ FROM kibana_sample_data_ecommerce
 | WHERE order_date >= ?_tstart and order_date <= ?_tend
 ----
 
-image::images/esql-custom-time-series.png[ESQL query with a custom time field enabled]
-
-
-[float]
-==== ES|QL and LOOKUP JOINs
-
-The ES|QL editor supports {ref}/esql-commands.html#esql-lookup-join[`LOOKUP JOIN`] commands and suggests lookup mode indices and join condition fields.
-
-image::https://images.contentstack.io/v3/assets/bltefdd0b53724fa2ce/blte43a30a93241d650/67c23670045f5839e5bfd1e4/lookup-join-demo.gif[Using the LOOKUP JOIN command to autocomplete an ES|QL query]
-
+image::images/esql-custom-time-series.png[ESQL query with a custom time field enabled]