feat: add user-defined settings live-reloading

- The settings are automatically reloaded when the `doom_config.lua` file was changed

  - The settings can be reloaded manually by pressing `SPC - d - l`

lua/doom/core/functions/init.lua

@@ -76,6 +76,17 @@ M.load_custom_settings = function(settings_tbl, scope)
   end
 end
 
+-- reload_custom_settings reloads all the user-defined configurations
+-- in the 'doom_config.lua' file.
+M.reload_custom_settings = function()
+  -- Get the user-defined settings, the 'nvim' field in our 'doom_config.lua'
+  local custom_settings = require("doom.core.config").load_config().nvim
+  -- iterate over all the custom settings fields, e.g. global_variables, mappings, etc.
+  for scope, _ in pairs(custom_settings) do
+    M.load_custom_settings(custom_settings[scope], scope)
+  end
+end
+
 -- Quit Neovim and change the colorscheme at doomrc if the colorscheme is not the same,
 -- dump all messages to doom.log file
 -- @tparam bool write If doom should save before exiting

lua/doom/extras/autocmds/init.lua

@@ -18,6 +18,12 @@ local autocmds = {
       "*/doom-*.lua,doomrc.lua,plugins.lua",
       "PackerCompile profile=true",
     },
+    -- Reload user-defined settings when 'doom_config.lua' file was modified
+    {
+      "BufWritePost",
+      "doom_config.lua",
+      "lua require('doom.core.functions').reload_user_settings()",
+    },
   },
   doom_extras = {
     -- Set up vim_buffer_previewer in telescope.nvim
@@ -101,10 +107,10 @@ if config.doom.preserve_edit_pos then
     "BufReadPost",
     "*",
     [[
-            if line("'\"") > 1 && line("'\"") <= line("$") |
-                exe "normal! g'\"" |
-            endif
-        ]],
+      if line("'\"") > 1 && line("'\"") <= line("$") |
+        exe "normal! g'\"" |
+      endif
+    ]],
   })
 end
 

lua/doom/extras/keybindings/init.lua

@@ -583,6 +583,15 @@ utils.map(
   "show_keybindings",
   "Show Doom keybindings"
 )
+utils.map(
+  "n",
+  "<leader>dl",
+  "<cmd>lua require('doom.core.functions').reload_custom_settings()<CR>",
+  opts,
+  "Doom",
+  "reload_user_settings",
+  "Reload user custom settings"
+)
 
 -- Plugins
 utils.map(

lua/doom/modules/config/doom-whichkey.lua

@@ -110,6 +110,7 @@ return function()
       ["r"] = { "Rollback Doom Nvim version" },
       ["R"] = { "Create crash report" },
       ["s"] = { "Change colorscheme" },
+      ["l"] = { "Reload user custom settings" },
     },
     ["f"] = {
       name = "+file",