Generate inaccessible while waiting if necessary

src/api/chainHead_unstable_storage.md

@@ -83,6 +83,8 @@ The `waiting-for-continue` event is generated after at least one `"item"` event
 
 This event only ever happens if the `type` parameter was `descendants-values` or `descendants-hashes`.
 
+While the JSON-RPC server is waiting for a call to `chainHead_unstable_storageContinue`, it can generate an `inaccessible` event in order to indicate that it can no longer proceed with the request. If that is the case, the JSON-RPC client can simply try again.
+
 ### done
 
 ```json

src/api/chainHead_unstable_storageContinue.md

@@ -8,6 +8,8 @@
 
 Resumes a storage fetch started with `chainHead_unstable_storage` after it has generated a `waiting-for-continue` event.
 
+Has no effect if the `subscription` is invalid or refers to a subscription that has emitted a `{"event": "inaccessible"}` event.
+
 ## Possible errors
 
-- A JSON-RPC error is generated if the `subscription` is invalid or hasn't generated a `waiting-for-continue` event.
+- A JSON-RPC error is generated if the `subscription` hasn't generated a `waiting-for-continue` event.