archive: Add stop method

Signed-off-by: Alexandru Vasile <[email protected]>

Author: lexnv

src/api/archive_unstable_stopStorageDiff.md

@@ -0,0 +1,11 @@
+# archive_unstable_stopStorageDiff
+
+**Parameters**:
+
+- An opaque string that was returned by `archive_unstable_StorageDiff`.
+
+**Return value**: *null*
+
+Stops a subscription started with `archive_unstable_StorageDiff`. Has no effect if the opaque string is invalid or refers to a subscription that has already emitted a `{"event": "storageDiffDone"}` event.
+
+JSON-RPC client implementations must be aware that, due to the asynchronous nature of JSON-RPC client <-> server communication, they might still receive chain updates notifications, for example because these notifications were already in the process of being sent back by the JSON-RPC server.