Fixed condition check on item existence in list

Previously, 'set $path...' ran regardless of the result of 'and not contains...'. This fixes _append_path to actually use the result of the condition check.

functions/_append_path.fish

@@ -7,7 +7,9 @@ function _append_path
     set path $argv[2]
   end
 
-  if test -d $argv[1]; and not contains $argv[1] $$path
-    set $path $argv[1] $$path
+  if test -d $argv[1]
+    if not contains $argv[1] $$path
+      set $path $argv[1] $$path
+    end
   end
 end