[Docs] Correct response json in rank-eval.asciidoc

docs/reference/search/rank-eval.asciidoc

@@ -287,7 +287,7 @@ that shows potential errors of individual queries. The response has the followin
                     "docs_retrieved": 10
                 }
             },
-            "my_query_id2 : { [...]} 
+            "my_query_id2" : { [...] }
         },
         "failures": { [...] }
     }