fixed termguicolors not working on tmux with neovim

tmux/tmux.conf

@@ -39,10 +39,7 @@ unbind %
 set -g mouse off
 
 # Set the default terminal
-set -s default-terminal 'tmux-256color'
-
-# Set the correct terminal feature for better termguicolors in Neovim
-set-option -sa terminal-features ',XXX:RGB'
+set -s default-terminal 'alacritty'
 
 # open/split window with current path
 bind '"' split-window -c "#{pane_current_path}"
@@ -52,6 +49,9 @@ bind c new-window -c "#{pane_current_path}"
 # Longer workspace names
 set -g status-left-length 20
 
+# Terminal feature specific to Neovim
+set-option -sa terminal-overrides ',alacritty:Tc'
+
 # Tmux plugins
 set -g @plugin "janoamaral/tokyo-night-tmux"
 set -g @plugin 'tmux-plugins/tpm'