[docs] Add bot token unmerge endpoint documentation (#7886)

* Add bot token unmerge endpoint documentation

Document the new /provisional-accounts/unmerge/bot endpoint that allows unmerging provisional accounts using just the bot token and external_user_id, without requiring an external auth token. This ensures identities can always be removed even if the external auth token is no longer accessible.

* Review edit

Add "Tip" for being able to recover an account that's lost its auth
token due to data loss or error.

---------

Co-authored-by: Mark Mandel <[email protected]>

Author: spenhand

discord/developers/docs/discord-social-sdk/development-guides/using-provisional-accounts.mdx

@@ -496,6 +496,32 @@ def unmerge_provisional_account(external_auth_token):
 If you have a server backend, you'll want to use the server-to-server unmerge endpoint rather than the SDK helper method to maintain better security and control over the unmerge process.
 </Info>
 
+#### Unmerging with Bot Token Endpoint
+
+If you're using the [Bot Token Endpoint](/docs/discord-social-sdk/development-guides/using-provisional-accounts#server-authentication-with-bot-token-endpoint) for authentication, you can unmerge accounts without an external auth token.
+
+```python
+import requests
+
+API_ENDPOINT = 'https://discord.com/api/v10'
+BOT_TOKEN = 'YOUR_BOT_TOKEN'
+
+def unmerge_provisional_account(external_user_id):
+  data = {
+    'external_user_id': external_user_id # identifier used in the /token/bot endpoint
+  }
+  headers = {
+    'Content-Type': 'application/json',
+    'Authorization': f'Bot {BOT_TOKEN}'
+  }
+  r = requests.post('%s/provisional-accounts/unmerge/bot' % API_ENDPOINT, json=data, headers=headers)
+  r.raise_for_status()
+```
+
+<Tip>
+This endpoint can also be useful in cases where the Discord Auth token has been lost to to error or data loss, and an unmerge operation is required to migrate to a provisional account before re-linking a Discord account.
+</Tip>
+
 ### Unmerging Provisional Accounts for Public Clients
 
 <PublicClient />
@@ -621,4 +647,4 @@ import {UserStatusIcon} from '/snippets/icons/UserStatusIcon.jsx'
 [`Client::GetTokenFromProvisionalMerge`]: https://discord.com/developers/docs/social-sdk/classdiscordpp_1_1Client.html#a41062b7dafa331ddd2320daf1b4b273b
 [`Client::SetTokenExpirationCallback`]: https://discord.com/developers/docs/social-sdk/classdiscordpp_1_1Client.html#aab5bfc76809ea22e79f2f7a067ac4519
 [`Client::UnmergeIntoProvisionalAccount`]: https://discord.com/developers/docs/social-sdk/classdiscordpp_1_1Client.html#a2da21ae8a3015e0e5e42c1a7226b256f
-[`Client::UpdateProvisionalAccountDisplayName`]: https://discord.com/developers/docs/social-sdk/classdiscordpp_1_1Client.html#a7485979ab2d4c533b75f8efd5e50bc60
+[`Client::UpdateProvisionalAccountDisplayName`]: https://discord.com/developers/docs/social-sdk/classdiscordpp_1_1Client.html#a7485979ab2d4c533b75f8efd5e50bc60