docs: update expr mapping for <c-i>/tab (#47)

Co-authored-by: tris203 <[email protected]>

Author: skoch13

README.md

@@ -28,35 +28,43 @@ return {
         vim.g.copilot_nes_debounce = 500
         vim.lsp.enable("copilot_ls")
         vim.keymap.set("n", "<tab>", function()
-            -- Try to jump to the start of the suggestion edit.
-            -- If already at the start, then apply the pending suggestion and jump to the end of the edit.
-            local _ = require("copilot-lsp.nes").walk_cursor_start_edit()
-                or (
-                    require("copilot-lsp.nes").apply_pending_nes() and require("copilot-lsp.nes").walk_cursor_end_edit()
-                )
-        end)
+            local bufnr = vim.api.nvim_get_current_buf()
+            local state = vim.b[bufnr].nes_state
+            if state then
+                -- Try to jump to the start of the suggestion edit.
+                -- If already at the start, then apply the pending suggestion and jump to the end of the edit.
+                local _ = require("copilot-lsp.nes").walk_cursor_start_edit()
+                    or (
+                        require("copilot-lsp.nes").apply_pending_nes()
+                        and require("copilot-lsp.nes").walk_cursor_end_edit()
+                    )
+                return nil
+            else
+                -- Resolving the terminal's inability to distinguish between `TAB` and `<C-i>` in normal mode
+                return "<C-i>"
+            end
+        end, { desc = "Accept Copilot NES suggestion", expr = true })
     end,
 }
 ```
 
-
 #### Clearing suggestions with Escape
 
 You can map the `<Esc>` key to clear suggestions while preserving its other functionality:
 
 ```lua
 -- Clear copilot suggestion with Esc if visible, otherwise preserve default Esc behavior
 vim.keymap.set("n", "<esc>", function()
-    if not require('copilot-lsp.nes').clear() then
+    if not require("copilot-lsp.nes").clear() then
         -- fallback to other functionality
     end
 end, { desc = "Clear Copilot suggestion or fallback" })
 ```
 
 ## Default Configuration
 
-
 ### NES (Next Edit Suggestion) Smart Clearing
+
 You don’t need to configure anything, but you can customize the defaults:
 `move_count_threshold` is the most important. It controls how many cursor moves happen before suggestions are cleared. Higher = slower to clear.
 
@@ -68,7 +76,6 @@ require('copilot-lsp').setup({
 })
 ```
 
-
 ### Blink Integration
 
 ```lua