[docs] refetchQueries should allow query name string

`refetchQueries` should allow array of query name string or `{ query: DocumentNode, variables?: TVariables}`.

docs/source/essentials/mutations.md

@@ -234,7 +234,7 @@ The Mutation component accepts the following props. Only `mutation` and `childre
   <dd>If true, the `data` property on the render prop function will not update with the mutation result.</dd>
   <dt>`optimisticResponse`: Object</dt>
   <dd>Provide a [mutation response](../features/optimistic-ui.html) before the result comes back from the server</dd>
-  <dt>`refetchQueries`: (mutationResult: FetchResult) => Array<{ query: DocumentNode, variables?: TVariables}></dt>
+  <dt>`refetchQueries`: (mutationResult: FetchResult) => Array<{ query: DocumentNode, variables?: TVariables} | string></dt>
   <dd>A function that allows you to specify which queries you want to refetch after a mutation has occurred</dd>
   <dt>`onCompleted`: (data: TData) => void</dt>
   <dd>A callback executed once your mutation successfully completes</dd>