2765 mixpanel update (#2767)

* Add Vidora to allow list

* Added requested section to Mixpanel Identify

Author: markzegarelli

src/connections/destinations/catalog/mixpanel/index.md

@@ -73,6 +73,12 @@ analytics.identify('userId123', {
 
 The first thing you'll want to do is to identify your users so Mixpanel knows who they are. You'll use the Identify method to accomplish this which takes the unique `userId` of a user and any `traits` you know about them.
 
+> info ""
+> **Important:** Mixpanel used to require that you call `alias` in all libraries to connect anonymous visitors to identified users. However, with the release of Mixpanel's new [Identity Merge feature](https://help.mixpanel.com/hc/en-us/articles/360039133851#enable-id-merge) this is no longer necessary. To enable ID Merge, go to your Mixpanel Settings Dashboard, navigate to **Project Settings > Identity Merge** and enable the setting from that screen. If you are _not_ using this setting, use the instructions below.
+
+
+As soon as you have a `userId` for a visitor that was previously anonymous you'll need to [`alias`](/docs/connections/spec/alias/) their old anonymous `id` to the new `userId`. In Mixpanel only **one** anonymous user history can be merged to **one** identified user. For that reason you should only call `alias` once, right after a user registered, but before the first `identify`.
+
 ### People
 
 Segment doesn't send data to Mixpanel People by default, since this usually requires upgrading your Mixpanel account. To enable Mixpanel People, change the "Use Mixpanel People" setting in the Mixpanel Destination settings in Segment.