I think it is a good idea to also split the autocomplete module, but in a separated repo/plugin. Because although they are both related to kamailio.cfg they are intended for different tasks/purposes.
I have installed the syntax plugin but not the autocomplete, as there are several general purpose autocomplete plugins, and installing more than one is troublesome.
As I'm already using Ultisnips I intended to check the snippets defined there later and then translate then for Ultisnips/Snipmate format when I have some spare time.