[6.2] [Docs] Add example for updating meta field (#35893) (#38006)

Author: geekpete

docs/reference/mapping/fields/meta-field.asciidoc

@@ -27,4 +27,20 @@ PUT my_index
     <<indices-get-mapping,GET mapping>> API.
 
 The `_meta` field can be updated on an existing type using the
-<<indices-put-mapping,PUT mapping>> API.
+<<indices-put-mapping,PUT mapping>> API:
+
+[source,js]
+--------------------------------------------------
+PUT my_index/_mapping/user
+{
+  "_meta": {
+    "class": "MyApp2::User3",
+    "version": {
+      "min": "1.3",
+      "max": "1.5"
+    }
+  }
+}
+--------------------------------------------------
+// CONSOLE
+// TEST[continued]