[SPEC] Added force to indices.refresh

rest-api-spec/api/indices.refresh.json

@@ -26,6 +26,11 @@
             "default" : "open",
             "description" : "Whether to expand wildcard expression to concrete indices that are open, closed or both."
         },
+        "force": {
+            "type" : "boolean",
+            "description" : "Force a refresh even if not required",
+            "default": false
+        },
         "operation_threading": {
           "description" : "TODO: ?"
         }