Clarify that restricted joins require the referenced user to be joined (#2220)

changelogs/room_versions/newsfragments/2220.clarification

@@ -0,0 +1 @@
+In room versions 8 through 12, clarify that "sufficient permission to invite users" on restricted joins also includes being a joined member of the room.

content/rooms/fragments/v8-auth-rules.md

@@ -74,7 +74,7 @@ The rules are as follows:
             1.  If membership state is `join` or `invite`, allow.
             2.  If the `join_authorised_via_users_server` key in `content`
                 is not a user with sufficient permission to invite other
-                users, reject.
+                users or is not a joined member of the room, reject.
             3.  Otherwise, allow.
         6.  If the `join_rule` is `public`, allow.
         7.  Otherwise, reject.

content/rooms/v10.md

@@ -150,7 +150,7 @@ The rules are as follows:
             1.  If membership state is `join` or `invite`, allow.
             2.  If the `join_authorised_via_users_server` key in `content`
                 is not a user with sufficient permission to invite other
-                users, reject.
+                users or is not a joined member of the room, reject.
             3.  Otherwise, allow.
         6.  If the `join_rule` is `public`, allow.
         7.  Otherwise, reject.

content/rooms/v11.md

@@ -157,7 +157,7 @@ The rules are as follows:
             1.  If membership state is `join` or `invite`, allow.
             2.  If the `join_authorised_via_users_server` key in `content`
                 is not a user with sufficient permission to invite other
-                users, reject.
+                users or is not a joined member of the room, reject.
             3.  Otherwise, allow.
         6.  If the `join_rule` is `public`, allow.
         7.  Otherwise, reject.

content/rooms/v12.md

@@ -141,7 +141,7 @@ The rules are as follows:
             1.  If membership state is `join` or `invite`, allow.
             2.  If the `join_authorised_via_users_server` key in `content`
                 is not a user with sufficient permission to invite other
-                users, reject.
+                users or is not a joined member of the room, reject.
             3.  Otherwise, allow.
         6.  If the `join_rule` is `public`, allow.
         7.  Otherwise, reject.