Hi @Chaz and welcome to the Forum!
As @Ben_Brenner mentioned, there is no longer possible to turn a Task into a section adding a semi-colon. This is due to some updates and adjusts Asana had to make to implement new features. (You can read more about it in this post: "Tab+N" our new shortcut to create Sections)
With that said, the extension @Bastien_Siebman mentioned should allow you to do it.
I hope this helps!