use XDG_DATA_HOME for resurrect-dir path

Author: xlucn

scripts/helpers.sh

@@ -1,4 +1,8 @@
-default_resurrect_dir="$HOME/.tmux/resurrect"
+if [ -d "$HOME/.tmux/resurrect" ]; then
+        default_resurrect_dir="$HOME/.tmux/resurrect"
+else
+        default_resurrect_dir="${XDG_DATA_HOME:-$HOME/.local/share}"/tmux/resurrect
+fi
 resurrect_dir_option="@resurrect-dir"
 
 SUPPORTED_VERSION="1.9"