update docs

Author: idegtiarenko

docs/reference/esql/functions/description/hash.asciidoc

@@ -13,6 +13,7 @@
 * <<esql-concat>>
 * <<esql-ends_with>>
 * <<esql-from_base64>>
+* <<esql-hash>>
 * <<esql-left>>
 * <<esql-length>>
 * <<esql-locate>>
@@ -37,6 +38,7 @@ include::layout/byte_length.asciidoc[]
 include::layout/concat.asciidoc[]
 include::layout/ends_with.asciidoc[]
 include::layout/from_base64.asciidoc[]
+include::layout/hash.asciidoc[]
 include::layout/left.asciidoc[]
 include::layout/length.asciidoc[]
 include::layout/locate.asciidoc[]

docs/reference/esql/functions/kibana/definition/hash.json

@@ -41,7 +41,10 @@ public class Hash extends EsqlScalarFunction {
     private final Expression alg;
     private final Expression input;
 
-    @FunctionInfo(returnType = "keyword", description = "Computes the hash of the input using java.security.MessageDigest.")
+    @FunctionInfo(
+        returnType = "keyword",
+        description = "Computes the hash of the input using various algorithms such as MD5, SHA, SHA-224, SHA-256, SHA-384, SHA-512."
+    )
     public Hash(
         Source source,
         @Param(name = "alg", type = { "keyword", "text" }, description = "Hash algorithm to use.") Expression alg,