Feat: Sort Discussions by File Name (#102)

This MR adds the ability to sort discussions by file name, rather than just by date.

This is an optional configuration that can be passed in on startup. The MR also introduces a test suite for the Lua code that runs through Neovim, so that the plugin can be fully tested with required dependencies and APIs.

Major props to @johnybx for the hard work on this change!

lua/gitlab/actions/discussions/annotations.lua

@@ -0,0 +1,66 @@
+---@meta diagnostics
+
+---@class Author
+---@field id integer
+---@field username string
+---@field email string
+---@field name string
+---@field state string
+---@field avatar_url string
+---@field web_url string
+
+---@class LinePosition
+---@field line_code string
+---@field type string
+
+---@class GitlabLineRange
+---@field start LinePosition
+---@field end LinePosition
+
+---@class NotePosition
+---@field base_sha string
+---@field start_sha string
+---@field head_sha string
+---@field position_type string
+---@field new_path string?
+---@field new_line integer?
+---@field old_path string?
+---@field old_line integer?
+---@field line_range GitlabLineRange?
+
+---@class Note
+---@field id integer
+---@field type string
+---@field body string
+---@field attachment string
+---@field title string
+---@field file_name string
+---@field author Author
+---@field system boolean
+---@field expires_at string?
+---@field updated_at string?
+---@field created_at string?
+---@field noteable_id integer
+---@field noteable_type string
+---@field commit_id string
+---@field position NotePosition
+---@field resolvable boolean
+---@field resolved boolean
+---@field resolved_by Author
+---@field resolved_at string?
+---@field noteable_iid integer
+
+---@class UnlinkedNote: Note
+---@field position nil
+
+---@class Discussion
+---@field id string
+---@field individual_note boolean
+---@field notes Note[]
+
+---@class UnlinkedDiscussion: Discussion
+---@field notes UnlinkedNote[]
+
+---@class DiscussionData
+---@field discussions Discussion[]
+---@field unlinked_discussions UnlinkedDiscussion[]