Fix docs sample to not break at next version bump (#96754)

* Fix docs sample to not break at next version bump

* Use {version} substitution rather than hardcoding

Author: williamrandolph

docs/reference/migration/apis/feature-migration.asciidoc

@@ -56,93 +56,92 @@ Example response:
   "features" : [
     {
       "feature_name" : "async_search",
-      "minimum_index_version" : "8.0.0",
+      "minimum_index_version" : "{version}",
       "migration_status" : "NO_MIGRATION_NEEDED",
       "indices" : [ ]
     },
     {
       "feature_name" : "enrich",
-      "minimum_index_version" : "8.0.0",
+      "minimum_index_version" : "{version}",
       "migration_status" : "NO_MIGRATION_NEEDED",
       "indices" : [ ]
     },
     {
       "feature_name" : "ent_search",
-      "minimum_index_version" : "8.0.0",
+      "minimum_index_version" : "{version}",
       "migration_status" : "NO_MIGRATION_NEEDED",
       "indices" : [ ]
     },
     {
       "feature_name" : "fleet",
-      "minimum_index_version" : "8.0.0",
+      "minimum_index_version" : "{version}",
       "migration_status" : "NO_MIGRATION_NEEDED",
       "indices" : [ ]
     },
     {
       "feature_name" : "geoip",
-      "minimum_index_version" : "8.0.0",
+      "minimum_index_version" : "{version}",
       "migration_status" : "NO_MIGRATION_NEEDED",
       "indices" : [ ]
     },
     {
       "feature_name" : "kibana",
-      "minimum_index_version" : "8.0.0",
+      "minimum_index_version" : "{version}",
       "migration_status" : "NO_MIGRATION_NEEDED",
       "indices" : [ ]
     },
     {
       "feature_name" : "logstash_management",
-      "minimum_index_version" : "8.0.0",
+      "minimum_index_version" : "{version}",
       "migration_status" : "NO_MIGRATION_NEEDED",
       "indices" : [ ]
     },
     {
       "feature_name" : "machine_learning",
-      "minimum_index_version" : "8.0.0",
+      "minimum_index_version" : "{version}",
       "migration_status" : "NO_MIGRATION_NEEDED",
       "indices" : [ ]
     },
     {
       "feature_name" : "searchable_snapshots",
-      "minimum_index_version" : "8.0.0",
+      "minimum_index_version" : "{version}",
       "migration_status" : "NO_MIGRATION_NEEDED",
       "indices" : [ ]
     },
     {
       "feature_name" : "security",
-      "minimum_index_version" : "8.0.0",
+      "minimum_index_version" : "{version}",
       "migration_status" : "NO_MIGRATION_NEEDED",
       "indices" : [ ]
     },
     {
       "feature_name" : "synonyms",
-      "minimum_index_version" : "8.9.0",
+      "minimum_index_version" : "{version}",
       "migration_status" : "NO_MIGRATION_NEEDED",
       "indices" : [ ]
     },
     {
       "feature_name" : "tasks",
-      "minimum_index_version" : "8.0.0",
+      "minimum_index_version" : "{version}",
       "migration_status" : "NO_MIGRATION_NEEDED",
       "indices" : [ ]
     },
     {
       "feature_name" : "transform",
-      "minimum_index_version" : "8.0.0",
+      "minimum_index_version" : "{version}",
       "migration_status" : "NO_MIGRATION_NEEDED",
       "indices" : [ ]
     },
     {
       "feature_name" : "watcher",
-      "minimum_index_version" : "8.0.0",
+      "minimum_index_version" : "{version}",
       "migration_status" : "NO_MIGRATION_NEEDED",
       "indices" : [ ]
     }
   ],
   "migration_status" : "NO_MIGRATION_NEEDED"
 }
 --------------------------------------------------
-// TESTRESPONSE[s/"minimum_index_version" : "8.0.0"/"minimum_index_version" : $body.$_path/]
 
 
 When you submit a POST request to the `_migration/system_features` endpoint to