Added the API definition for updating the mapping

rest-api-spec/api/indices.mapping.put.json

@@ -1,24 +1,30 @@
 {
   "indices.mapping.put": {
-    "documentation": "",
+    "documentation": "http://www.elasticsearch.org/guide/reference/api/admin-indices-put-mapping/",
     "methods": ["PUT", "POST"],
     "url": {
       "path": "/{index}/_mapping",
       "paths": ["/{index}/_mapping", "/{index}/{type}/_mapping"],
       "parts": {
         "index": {
+          "type" : "list",
+          "required" : true,
+          "description" : "A comma-separated list of index names; use `_all` to perform the operation on all indices"
         },
         "type": {
+          "type" : "string",
+          "required" : true,
+          "description" : "The name of the document type"
         }
       },
       "params": {
         "ignore_conflicts": {
-        },
-        "index": {
+          "type" : "boolean",
+          "description" : "Specify whether to ignore conflicts while updating the mapping (default: false)"
         },
         "timeout": {
-        },
-        "type": {
+          "type" : "time",
+          "description" : "Explicit operation timeout"
         }
       }
     },