feature: git: Using delta as difftool

This also enables highlighting in the fzf-fish for git-related searches

home.nix

@@ -40,6 +40,7 @@
     fzf
     fd
     bat
+    delta
     # # It is sometimes useful to fine-tune packages, for example, by applying
     # # overrides. You can do that directly here, just don't forget the
     # # parentheses. Maybe you want to install Nerd Fonts with a limited number of
@@ -94,6 +95,9 @@
   programs.home-manager.enable = true;
   programs.fish = {
     enable = true;
+    shellInit = ''
+      set fzf_diff_highlighter delta --paging=never --width=20
+    '';
     shellInitLast = ''
       zoxide init fish | source
     '';