Fix minor typo in whatsnew.html

Author: ychin

release-notes/whatsnew.html

@@ -9,7 +9,7 @@
 
     <!--
     This page serves as a list of recent release notes. By default all but the
-    latest release is hidden by the caller can use URL parameters to enable
+    latest release is hidden but the caller can use URL parameters to enable
     them. This is mostly for use in MacVim's internal What's New page.
 
     Use ?from=<rev_exclusive>&to=<rev_inclusive> to list a range of releases.