Document what Create a message does when from is a contact (#732)

The Create a message docs say `from` is always an admin, but a user or
lead `from` is accepted. Add a note to the operation in 2.10-2.17 and
Preview describing what happens.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

Author: pkubicki

descriptions/0/api.intercom.io.yaml

@@ -21764,7 +21764,7 @@ paths:
         the Message model that has been created.\n\n> \U0001F6A7 Retrieving Associated
         Conversations\n>\n> As this is a message, there will be no conversation present
         until the contact responds. Once they do, you will have to search for a contact's
-        conversations with the id of the message.\n"
+        conversations with the id of the message.\n\n{% admonition type=\"warning\" name=\"Messages from contacts\" %}\n`from` should be an admin. A request with a user or lead as `from` is not rejected: it creates a conversation initiated by that contact, as the Create a conversation endpoint (`POST /conversations`) does, and the `to`, `cc` and `bcc` fields are ignored. To create a conversation initiated by a contact, use `POST /conversations`.\n{% /admonition %}\n"
       responses:
         '200':
           description: admin message created

descriptions/2.10/api.intercom.io.yaml

@@ -7392,7 +7392,7 @@ paths:
         the Message model that has been created.\n\n> \U0001F6A7 Retrieving Associated
         Conversations\n>\n> As this is a message, there will be no conversation present
         until the contact responds. Once they do, you will have to search for a contact's
-        conversations with the id of the message.\n"
+        conversations with the id of the message.\n\n{% admonition type=\"warning\" name=\"Messages from contacts\" %}\n`from` should be an admin. A request with a user or lead as `from` is not rejected: it creates a conversation initiated by that contact, as the Create a conversation endpoint (`POST /conversations`) does, and the `to`, `cc` and `bcc` fields are ignored. To create a conversation initiated by a contact, use `POST /conversations`.\n{% /admonition %}\n"
       responses:
         '200':
           description: admin message created

descriptions/2.11/api.intercom.io.yaml

@@ -7484,7 +7484,7 @@ paths:
         the Message model that has been created.\n\n> \U0001F6A7 Retrieving Associated
         Conversations\n>\n> As this is a message, there will be no conversation present
         until the contact responds. Once they do, you will have to search for a contact's
-        conversations with the id of the message.\n"
+        conversations with the id of the message.\n\n{% admonition type=\"warning\" name=\"Messages from contacts\" %}\n`from` should be an admin. A request with a user or lead as `from` is not rejected: it creates a conversation initiated by that contact, as the Create a conversation endpoint (`POST /conversations`) does, and the `to`, `cc` and `bcc` fields are ignored. To create a conversation initiated by a contact, use `POST /conversations`.\n{% /admonition %}\n"
       responses:
         '200':
           description: admin message created

descriptions/2.12/api.intercom.io.yaml

@@ -7889,7 +7889,7 @@ paths:
         the Message model that has been created.\n\n> \U0001F6A7 Retrieving Associated
         Conversations\n>\n> As this is a message, there will be no conversation present
         until the contact responds. Once they do, you will have to search for a contact's
-        conversations with the id of the message.\n"
+        conversations with the id of the message.\n\n{% admonition type=\"warning\" name=\"Messages from contacts\" %}\n`from` should be an admin. A request with a user or lead as `from` is not rejected: it creates a conversation initiated by that contact, as the Create a conversation endpoint (`POST /conversations`) does, and the `to`, `cc` and `bcc` fields are ignored. To create a conversation initiated by a contact, use `POST /conversations`.\n{% /admonition %}\n"
       responses:
         '200':
           description: admin message created

descriptions/2.13/api.intercom.io.yaml

@@ -9148,7 +9148,7 @@ paths:
         the Message model that has been created.\n\n> \U0001F6A7 Retrieving Associated
         Conversations\n>\n> As this is a message, there will be no conversation present
         until the contact responds. Once they do, you will have to search for a contact's
-        conversations with the id of the message.\n"
+        conversations with the id of the message.\n\n{% admonition type=\"warning\" name=\"Messages from contacts\" %}\n`from` should be an admin. A request with a user or lead as `from` is not rejected: it creates a conversation initiated by that contact, as the Create a conversation endpoint (`POST /conversations`) does, and the `to`, `cc` and `bcc` fields are ignored. To create a conversation initiated by a contact, use `POST /conversations`.\n{% /admonition %}\n"
       responses:
         '200':
           description: admin message created

descriptions/2.14/api.intercom.io.yaml

@@ -10871,7 +10871,7 @@ paths:
         the Message model that has been created.\n\n> \U0001F6A7 Retrieving Associated
         Conversations\n>\n> As this is a message, there will be no conversation present
         until the contact responds. Once they do, you will have to search for a contact's
-        conversations with the id of the message.\n"
+        conversations with the id of the message.\n\n{% admonition type=\"warning\" name=\"Messages from contacts\" %}\n`from` should be an admin. A request with a user or lead as `from` is not rejected: it creates a conversation initiated by that contact, as the Create a conversation endpoint (`POST /conversations`) does, and the `to`, `cc` and `bcc` fields are ignored. To create a conversation initiated by a contact, use `POST /conversations`.\n{% /admonition %}\n"
       responses:
         '200':
           description: admin message created

descriptions/2.15/api.intercom.io.yaml

@@ -10165,7 +10165,7 @@ paths:
         the Message model that has been created.\n\n> \U0001F6A7 Retrieving Associated
         Conversations\n>\n> As this is a message, there will be no conversation present
         until the contact responds. Once they do, you will have to search for a contact's
-        conversations with the id of the message.\n"
+        conversations with the id of the message.\n\n{% admonition type=\"warning\" name=\"Messages from contacts\" %}\n`from` should be an admin. A request with a user or lead as `from` is not rejected: it creates a conversation initiated by that contact, as the Create a conversation endpoint (`POST /conversations`) does, and the `to`, `cc` and `bcc` fields are ignored. To create a conversation initiated by a contact, use `POST /conversations`.\n{% /admonition %}\n"
       responses:
         '200':
           description: admin message created

descriptions/2.16/api.intercom.io.yaml

@@ -17225,7 +17225,7 @@ paths:
         the Message model that has been created.\n\n> \U0001F6A7 Retrieving Associated
         Conversations\n>\n> As this is a message, there will be no conversation present
         until the contact responds. Once they do, you will have to search for a contact's
-        conversations with the id of the message.\n"
+        conversations with the id of the message.\n\n{% admonition type=\"warning\" name=\"Messages from contacts\" %}\n`from` should be an admin. A request with a user or lead as `from` is not rejected: it creates a conversation initiated by that contact, as the Create a conversation endpoint (`POST /conversations`) does, and the `to`, `cc` and `bcc` fields are ignored. To create a conversation initiated by a contact, use `POST /conversations`.\n{% /admonition %}\n"
       responses:
         '200':
           description: admin message created

descriptions/2.17/api.intercom.io.yaml

@@ -19719,7 +19719,7 @@ paths:
         the Message model that has been created.\n\n> \U0001F6A7 Retrieving Associated
         Conversations\n>\n> As this is a message, there will be no conversation present
         until the contact responds. Once they do, you will have to search for a contact's
-        conversations with the id of the message.\n"
+        conversations with the id of the message.\n\n{% admonition type=\"warning\" name=\"Messages from contacts\" %}\n`from` should be an admin. A request with a user or lead as `from` is not rejected: it creates a conversation initiated by that contact, as the Create a conversation endpoint (`POST /conversations`) does, and the `to`, `cc` and `bcc` fields are ignored. To create a conversation initiated by a contact, use `POST /conversations`.\n{% /admonition %}\n"
       responses:
         '200':
           description: admin message created