Added the API definition for getting a warmer

rest-api-spec/api/indices.warmer.get.json

@@ -1,23 +1,25 @@
 {
   "indices.warmer.get": {
-    "documentation": "",
+    "documentation": "http://www.elasticsearch.org/guide/reference/api/admin-indices-warmers/",
     "methods": ["GET"],
     "url": {
       "path": "/{index}/_warmer",
       "paths": ["/{index}/_warmer", "/{index}/_warmer/{name}", "/{index}/{type}/_warmer/{name}"],
       "parts": {
         "index": {
+          "type" : "list",
+          "description" : "A comma-separated list of index names to restrict the operation; use `_all` or empty string to perform the operation on all indices"
         },
         "name": {
+          "type" : "string",
+          "description" : "The name of the warmer (supports wildcards); leave empty to get all warmers"
         },
         "type": {
+          "type" : "list",
+          "description" : "A comma-separated list of document types to restrict the operation; leave empty to perform the operation on all types"
         }
       },
       "params": {
-        "index": {
-        },
-        "name": {
-        }
       }
     },
     "body": null