Docs: clarify project transfer permissions

doc/user/project/settings/index.md

@@ -100,9 +100,9 @@ Only project Owners and Admin users have the [permissions] to transfer a project
 
 You can transfer an existing project into a [group](../../group/index.md) if:
 
-1. you have at least **Maintainer** [permissions] to that group
-1. you are an **Owner** of the project.
-
+1. You have at least **Maintainer** [permissions] to that group.
+1. The project is in a subgroup you own.
+1. You are at least a **Maintainer** of the project under your personal namespace.
 Similarly, if you are an owner of a group, you can transfer any of its projects
 under your own user.