rephrase warning (#130691)

* rephrase warning

* Update docs/reference/elasticsearch/mapping-reference/mapping-source-field.md

Co-authored-by: Liam Thompson <leemthompo@gmail.com>

---------

Co-authored-by: Liam Thompson <leemthompo@gmail.com>

docs/reference/elasticsearch/mapping-reference/mapping-source-field.md

@@ -308,18 +308,19 @@ PUT my-index-000001
 }
 ```
 
-::::{admonition} Think before disabling the _source field
+::::{admonition} Disabling the `_source` field
 :class: warning
 
-Users often disable the `_source` field without thinking about the consequences, and then live to regret it. If the `_source` field isn’t available then a number of features are not supported:
+Do not disable the `_source` field, unless absolutely necessary. If you disable it, the following critical features will not be supported:
 
 * The [`update`](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-update), [`update_by_query`](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-update-by-query), and [`reindex`](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-reindex) APIs.
-* In the {{kib}} [Discover](docs-content://explore-analyze/discover.md) application, field data will not be displayed.
+* Display of field data in the {{kib}} [Discover](docs-content://explore-analyze/discover.md) application.
 * On the fly [highlighting](/reference/elasticsearch/rest-apis/highlighting.md).
 * The ability to reindex from one Elasticsearch index to another, either to change mappings or analysis, or to upgrade an index to a new major version.
 * The ability to debug queries or aggregations by viewing the original document used at index time.
 * Potentially in the future, the ability to repair index corruption automatically.
 
+
 ::::
 
 ::::{note}