cleanup: refactor which-key configuration for cleaner setup (#1102)

- Moved `which-key` configuration from inline `config` to `opts` for better organization.
- Updated the key mappings setup to use `spec` for defining existing key chains.
- Removed deprecated or unnecessary comments and code.

This change aligns with updated `which-key` configuration practices, improving readability and maintainability as recommended by @VlaDexa in #1068.

init.lua

@@ -274,8 +274,7 @@ require('lazy').setup({
   { -- Useful plugin to show you pending keybinds.
     'folke/which-key.nvim',
     event = 'VimEnter', -- Sets the loading event to 'VimEnter'
-    config = function() -- This is the function that runs, AFTER loading
-      require('which-key').setup {
+    opts = {
       icons = {
         -- set icon mappings to true if you have a Nerd Font
         mappings = vim.g.have_nerd_font,
@@ -311,11 +310,9 @@ require('lazy').setup({
           F11 = '<F11>',
           F12 = '<F12>',
         },
-        },
-      }
 
         -- Document existing key chains
-      require('which-key').add {
+        spec = {
           { '<leader>c', group = '[C]ode', mode = { 'n', 'x' } },
           { '<leader>d', group = '[D]ocument' },
           { '<leader>r', group = '[R]ename' },
@@ -323,8 +320,9 @@ require('lazy').setup({
           { '<leader>w', group = '[W]orkspace' },
           { '<leader>t', group = '[T]oggle' },
           { '<leader>h', group = 'Git [H]unk', mode = { 'n', 'v' } },
-      }
-    end,
+        },
+      },
+    },
   },
 
   -- NOTE: Plugins can specify dependencies.