feat(lsp): add snippet support and refactor completion into Item class

lua/core/keymap.lua

@@ -162,6 +162,18 @@ end)
 vim.keymap.set({ "i", "s" }, "<C-s>", function()
     vim.lsp.buf.signature_help({ max_width = 80 })
 end)
+---@param key string
+---@param dir 1 | -1
+local function snippet_jump_map(key, dir)
+    vim.keymap.set({ "i", "s" }, key, function()
+        if vim.snippet.active({ direction = dir }) then
+            return string.format("<cmd>lua vim.snippet.jump(%d)<CR>", dir)
+        end
+        return key
+    end, { expr = true, replace_keycodes = true })
+end
+snippet_jump_map("<Tab>", 1)
+snippet_jump_map("<S-Tab>", -1)
 vim.keymap.set({ "n", "i" }, "<C-h>", vim.lsp.buf.document_highlight)
 vim.keymap.set({ "n", "x" }, "<leader>lf", vim.lsp.buf.format)
 vim.keymap.set("n", "grl", function()
@@ -177,6 +189,7 @@ vim.keymap.set({ "n", "i" }, "<C-l>", function()
     vim.lsp.buf.clear_references()
     vim.cmd.nohlsearch()
     vim.schedule(vim.cmd.diffupdate)
+    vim.snippet.stop()
     return "<C-l>"
 end, { expr = true })
 vim.keymap.set("n", "<leader>fd", vim.diagnostic.setloclist)