Update CHANGELOG.md

Author: rly

CHANGELOG.md

@@ -3,7 +3,7 @@
 ## PyNWB 3.1.3 (Unreleased)
 
 ### Documentation and tutorial enhancements
-- Change UI if assistant to be an accordion that is always visible. [#2124](https://github.com/NeurodataWithoutBorders/pynwb/pull/2124)
+- Change UI of assistant to be an accordion that is always visible. [#2124](https://github.com/NeurodataWithoutBorders/pynwb/pull/2124)
 
 ## PyNWB 3.1.2 (August 13, 2025)