Fix changelog

Author: hoodmane

ChangeLog.md

@@ -27,7 +27,6 @@ See docs/process.md for more on how version tagging works.
 - mimalloc was updated to 2.1.7. (#21548)
 - The file system was updated to independently track atime, mtime and ctime
   instead of using the same time for all three. (#22998)
-- mimalloc was updated to 2.1.7. (#21548)
 
 3.1.72 - 11/19/24
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