Update nvm.sh with suggestions from ljharb

Co-Authored-By: Jordan Harband <[email protected]>

Author: aiqui

nvm.sh

@@ -313,7 +313,9 @@ nvm_tree_contains_path() {
   pathdir=$(dirname "${node_path}")
 
   # get real directory in case of symbolic links 
-  [ -d "${pathdir}" ] && pathdir="$( cd -P "${pathdir}" && pwd )"
+  if [ -d "${pathdir-}" ]; then
+    pathdir="$(nvm_cd -P "${pathdir}" && pwd)"
+  fi
 
   while [ "${pathdir}" != "" ] && [ "${pathdir}" != "." ] && [ "${pathdir}" != "/" ] && [ "${pathdir}" != "${tree}" ]; do
     pathdir=$(dirname "${pathdir}")