Add filter order

Python now serves as reference implementations. We've recently changed the order there, see getsentry/sentry-python#1394 and getsentry/sentry-python#1390

src/docs/sdk/sessions.mdx

@@ -509,3 +509,13 @@ Provide an easy way to integrate with existing Node frameworks (Express, Next.js
 ### Session update filtering
 
 Events may be dropped by our filtering mechanisms (sample rate, beforeSend, event processors or ignored exception types). Only events dropped due to sampling should update the session despite being dropped as we assume the event was dropped to save quota but would have been something the developer cares about. Events dropped due to other reasons should not update the session as we assume they are more likely to be dropped because the developer chooses to ignore them.
+
+#### Filter order
+
+The python SDK shall serve as a reference here. The order for filtering error events is:
+1. Check for ignored exception types (a.k.a `ignore_errors`)
+3. Apply scoped `event_processor` (a.k.a `error_processor`)
+4. Apply global `event_processor`
+2. Apply `before_send`
+5. Update the session if an event made it this far
+6. Apply sampling rate