fix changelog

Author: affeldt-aist

CHANGELOG_UNRELEASED.md

@@ -189,8 +189,6 @@
   + lemmas `Radon_NikodymE`, `Radon_Nikodym_fin_num`, `Radon_Nikodym_integrable`,
     `ae_eq_Radon_Nikodym_SigmaFinite`, `Radon_Nikodym_change_of_variables`,
     `Radon_Nikodym_cscale`, `Radon_Nikodym_cadd`, `Radon_Nikodym_chain_rule`
-  
-### Changed
 
 ### Renamed