Feed URL Generator misses Slash – php wp_list_categories(’sortby=name&feed=RSS’)

(I had accidentally posted this in the Installation category, so I have now closed that one.)

Update:
On the Options->General page, I tried setting the blog and site urls to have the ending slash in them, but upon saving changes (”Update Options”), WordPress automatically cut the trailing slashes. I tried / (forward slash) and \ (backslash, I believe).

The code:

<?php wp_list_categories(’sortby=name&feed=RSS’); ?>

produces:

http://www.example.com/category/caregiverfeed.
but we need
http://www.example.com/category/caregiver/feed.

categoryfeed is not a feed,
category/feed is a feed.

How do we get the php code to produce the missing forward-slash?

(Yes the feeds I manually entered work, but the list generated by the code above does not.)

In various combinations, I tried adding %2F, the [__] for a slash:

but I don’t know PHP, and none worked.

…name&”%2F”&feed…
…name&%2F&feed…
…name&/&feed…
…name’&’/’&feed…

(My blog, if you want to see it, is imagiscape.ca/blog.)