[DOCS] Rewrite prefix query docs (#41955)

Author: jrodewig

docs/reference/query-dsl/prefix-query.asciidoc

@@ -4,33 +4,66 @@
 <titleabbrev>Prefix</titleabbrev>
 ++++
 
-Matches documents that have fields containing terms with a specified
-prefix (*not analyzed*). The prefix query maps to Lucene `PrefixQuery`.
-The following matches documents where the user field contains a term
-that starts with `ki`:
+Returns documents that contain a specific prefix in a provided field.
+
+[[prefix-query-ex-request]]
+==== Example request
+
+The following search returns documents where the `user` field contains a term
+that begins with `ki`.
 
 [source,js]
---------------------------------------------------
+----
 GET /_search
-{ "query": {
-    "prefix" : { "user" : "ki" }
-  }
+{
+    "query": {
+        "prefix": {
+            "user": {
+                "value": "ki"
+            }
+        }
+    }
 }
---------------------------------------------------
+----
 // CONSOLE
 
-A boost can also be associated with the query:
+[[prefix-query-top-level-params]]
+==== Top-level parameters for `prefix`
+`<field>`::
+(Required, object) Field you wish to search.
+
+[[prefix-query-field-params]]
+==== Parameters for `<field>`
+`value`::
+(Required, string) Beginning characters of terms you wish to find in the
+provided `<field>`.
+
+`rewrite`::
+(Optional, string) Method used to rewrite the query. For valid values and more
+information, see the <<query-dsl-multi-term-rewrite, `rewrite` parameter>>.
+
+[[prefix-query-notes]]
+==== Notes
+
+[[prefix-query-short-ex]]
+===== Short request example
+You can simplify the `prefix` query syntax by combining the `<field>` and
+`value` parameters. For example:
 
 [source,js]
---------------------------------------------------
+----
 GET /_search
-{ "query": {
-    "prefix" : { "user" :  { "value" : "ki", "boost" : 2.0 } }
-  }
+{
+    "query": {
+        "prefix" : { "user" : "ki" }
+    }
 }
---------------------------------------------------
+----
 // CONSOLE
 
-This multi term query allows you to control how it gets rewritten using the
-<<query-dsl-multi-term-rewrite,rewrite>>
-parameter.
+[[prefix-query-index-prefixes]]
+===== Speed up prefix queries
+You can speed up prefix queries using the <<index-prefixes,`index_prefixes`>>
+mapping parameter. If enabled, {es} indexes prefixes between 2 and 5
+characters in a separate field. This lets {es} run prefix queries more
+efficiently at the cost of a larger index.