Smarter sort_by_kind: make functions prior after ::

[zjp-CN]

Currently, sort_by_kind is sorting from a fixed list.

Given the default kind ordering in this plugin, Method is always prior to Function, then it works fine after typing ., but not fine after typing :: which will likely call a function.

The problem can be mitigated by dynamically setting :lua rs.kind.set({"Function", "Method"}), but lacks inherent vs trait sorting on Functions.

Anyway, this is a hole that indicates we need more refined sorting based on trigger text. For this problem, the smarter sorting needs to

• know trigger text
• control kind list
• handle inherent vs trait