feat(fish): Add dotfiles update notice

fish/config.fish

@@ -100,7 +100,20 @@ end
 
 bind -e \cv
 
-## Start tmux by default
+# Check if dotfiles have any updates
+function check_config_git_status
+  set config_dir $HOME/.config
+  if test -d $config_dir/.git
+    set dotfiles_status (git -C $config_dir status --porcelain)
+    if test -n "$dotfiles_status"
+      echo (set_color yellow)"[.config] There are uncommitted changes or untracked files."(set_color normal)
+    end
+  end
+end
+
+check_config_git_status
+
+# Start tmux by default
 if status is-interactive
 and not set -q TMUX
     exec tmux