docs: fix a typo in a fragment

changelog.d/20220802_081039_nedbat.rst

@@ -3,6 +3,6 @@ Fixed
 
 - If there were no fragments to collect, `scriv collect` would make a new empty
   section in the changelog.  This was wrong, and is now fixed. Now the
-  changelog remained unchanged in this case.  Closes `issue 55`_.
+  changelog remains unchanged in this case.  Closes `issue 55`_.
 
 .. _issue 55: https://github.com/nedbat/scriv/issues/55