up.nu fixed (#252)

fix for version 0.64

filesystem/up.nu

@@ -1,10 +1,14 @@
 def up_inner [limit: int] {
-  (for $e in 0..$limit { "." } | str collect)
+  for $e in 0..$limit { "." }
+  | str collect
 }
 
 # Go up a number of directories
 def-env up [
     limit: int # The number of directories to go up
   ] {
-    cd (up_inner $limit)
-}
+    cd (
+    (up_inner $limit)
+    | into string
+    )
+}