Ensure XDG_RUNTIME_DIR is set in #fish

fish/.config/fish/config.fish

@@ -4,4 +4,5 @@ fzf_key_bindings
 set -gx PATH ~/.asdf/installs/rust/stable/bin $PATH
 set -gx PATH ~/.emacs.d/bin $PATH
 set -gx EDITOR vim $EDITOR
+set -gx XDG_RUNTIME_DIR /run/user/(id -u) $XDG_RUNTIME_DIR
 eval (python -m virtualfish)