[DOCS] Add redirect for SLM API docs (#46838)

docs/reference/redirects.asciidoc

@@ -833,4 +833,8 @@ See <<ccs-works>>.
 
 [role="exclude",id="administer-elasticsearch"]
 === Administering {es}
-See <<high-availability>>.
+See <<high-availability>>.
+
+[role="exclude",id="slm-api"]
+=== Snapshot lifecycle management API
+See <<snapshot-lifecycle-management-api>>.

x-pack/plugin/src/test/resources/rest-api-spec/api/slm.get_stats.json

@@ -1,7 +1,7 @@
 {
   "slm.get_stats":{
     "documentation":{
-      "url":"https://www.elastic.co/guide/en/elasticsearch/reference/current/slm-api.html"
+      "url":"https://www.elastic.co/guide/en/elasticsearch/reference/master/slm-get-stats.html"
     },
     "stability":"stable",
     "url":{