Clarify optional mock behaviour a little in README

README.md

@@ -813,7 +813,7 @@ var scope = nock('http://api.myservice.com')
 
 ## Optional Requests
 
-By default every mocked request is expected to be made exactly once, and until it is it'll appear in `scope.pendingMocks()`, and `scope.isDone()` will return false (see [expectations](#expectations)). In many cases this is fine, but in some (especially cross-test setup code) it's useful to be able to mock a request that may or may not happen. You can do this with `optionally()`. Optional requests do not appear in `pendingMocks()`, and `isDone()` will return true for scopes with only optional requests pending.
+By default every mocked request is expected to be made exactly once, and until it is it'll appear in `scope.pendingMocks()`, and `scope.isDone()` will return false (see [expectations](#expectations)). In many cases this is fine, but in some (especially cross-test setup code) it's useful to be able to mock a request that may or may not happen. You can do this with `optionally()`. Optional requests are consumed just like normal ones once matched, but they do not appear in `pendingMocks()`, and `isDone()` will return true for scopes with only optional requests pending.
 
 ```js
 var example = nock("http://example.com");