message: add example of using inspectFields to invalidate a list
diff: @@ -216,6 +216,27 @@ const cache = cacheExchange({
  });
  ```
  +Let's combine the above example with invalidating fields, imagine the scenario where we add a todo but
  +rather than manually pushing it on all the lists we just want to refetch the lists.
  +
  +```js
  +const cache = cacheExchange({
  + updates: {
  + Mutation: {
  + addTodo: (result, args, cache, info) => {
  + const todoQueries = cache.inspectFields('Query').filter(x => x.fieldName === 'todos');
  +
  + todosQueries.forEach(({ fieldName, arguments: variables }) => {
  + cache.invalidate('Query', fieldName, variables);
  + });
  + },
  + },
  + },
  +});
  +```
  +
  +Now when we come onto a list we'll know that this list needs to be refetched.
  +
  ## Optimistic updates
  If we know what result a mutation may return, why wait for the GraphQL API to fulfill our mutations?
  