put mapleader in the first line of `lua/core/keymaps.lua`

lua/core/keymaps.lua

@@ -1,3 +1,5 @@
+vim.g.mapleader = ';'
+
 local function set_bg_light()
 	vim.cmd('set background=light')
 	local colors_name = vim.g.colors_name
@@ -12,8 +14,6 @@ local function set_bg_dark()
 	vim.cmd('colorscheme ' .. colors_name)
 end
 
-vim.g.mapleader = ';'
-
 -- keymaps
 vim.keymap.set('i', '<C-g>', '<esc>')
 vim.keymap.set('i', '<C-;>', '::') -- for C++ and Rust