misc: Make exa man pages accessible

Even though it's possible to guarantee that a certain package is used,
it's still necessary to include packages in the $PATH in order to have
access to the man pages for them, among other things.

modules/fish-starship/default.nix

@@ -7,6 +7,7 @@ let VARIABLES = import ../../src/variables.nix; in {
   environment.systemPackages = with pkgs; [
     wget
     jq
+    exa
     fd
     fzf
     ripgrep