Merge branch 'fix/backslash-url-indices-put_mapping'

rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_mapping.json

@@ -8,7 +8,7 @@
     "url":{
       "paths":[
         {
-          "path":"{index}/_mapping",
+          "path":"/{index}/_mapping",
           "methods":[
             "PUT",
             "POST"