home: vim: completion: use 'vim.snippet'

I don't use any of the advanced features from `LuaSnip` anyway, might as
well rely on the built-in one instead and shave some dependencies.

modules/home/vim/default.nix

@@ -65,14 +65,12 @@ in
       plenary-nvim # 'null-ls', 'telescope' dependency
 
       # Completion
-      luasnip # Snippet manager compatible with LSP
       nvim-cmp # Completion engine
       cmp-async-path # More responsive path completion
       cmp-buffer # Words from open buffers
       cmp-nvim-lsp # LSP suggestions
       cmp-nvim-lua # NeoVim lua API
       cmp-under-comparator # Sort items that start with '_' lower
-      cmp_luasnip # Snippet suggestions from LuaSnip
 
       # UX improvements
       dressing-nvim # Integrate native UI hooks with Telescope etc...

modules/home/vim/plugin/settings/completion.lua

@@ -3,25 +3,24 @@ vim.opt.completeopt = { "menu", "menuone", "noselect" }
 
 local cmp = require("cmp")
 local cmp_under_comparator = require("cmp-under-comparator")
-local luasnip = require("luasnip")
 
 cmp.setup({
     snippet = {
         expand = function(args)
-            luasnip.lsp_expand(args.body)
+            vim.snippet.expand(args.body)
         end,
     },
     mapping = {
         ["<Tab>"] = function(fallback)
-            if luasnip.expand_or_jumpable() then
-                luasnip.expand_or_jump()
+            if vim.snippet.active({ direction = 1 }) then
+                vim.snippet.jump(1)
             else
                 fallback()
             end
         end,
         ["<S-Tab>"] = function(fallback)
-            if luasnip.jumpable(-1) then
-                luasnip.jump(-1)
+            if vim.snippet.active({ direction = -1 }) then
+                vim.snippet.jump(-1)
             else
                 fallback()
             end
@@ -40,7 +39,6 @@ cmp.setup({
         { name = "async_path", priority_weight = 110 },
         { name = "nvim_lsp", priority_weight = 100 },
         { name = "nvim_lua", priority_weight = 90 },
-        { name = "luasnip", priority_weight = 80 },
         { name = "buffer", max_item_count = 5, priority_weight = 50 },
     },
     sorting = {