Fix terminal colours within tmux

CHANGELOG.md

@@ -6,6 +6,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com), but adapt
 
 Instead of grouping changes by tag, they are grouped by the date they are released.
 
+## 19th December 2023
+
+### Fixed
+
+* Fix terminal colours within tmux.
+
 ## 18th December 2023
 
 ### Added

system/shared/modules/tmux.nix

@@ -17,7 +17,7 @@
       bind-key -n C-l select-pane -R
 
       set-option -g status-keys "emacs"
-      set-option -ga terminal-overrides ",*256col*:alacritty"
+      set-option -sa terminal-features "''${TERM}:RGB"
 
       bind-key h split-window -v  -c "#{pane_current_path}"
       bind-key v split-window -h  -c "#{pane_current_path}"