docs(changelog): improve it for what was already in

CHANGELOG.md

 ## Version 4.0.0 (2023-10-05)
-### 🎉 New features
+
+### 🎉 Code changes
 
 - run flynt on the code base to convert everything into f-strings
 - upgrade CubicWeb to version 4
@@ -7,7 +8,7 @@
 
 ### 📝 Documentation
 
-- licence: update licence dates
+licence: update licence dates
 
 ### 🤖 Continuous integration
 
@@ -11,6 +12,6 @@
 
 ### 🤖 Continuous integration
 
-- that tox option is now named allowlist_externals
+`tox` option `whitelist_externals` is now named `allowlist_externals`
 
 ## Version 3.3.1 (2023-01-17)
@@ -15,4 +16,3 @@
 
 ## Version 3.3.1 (2023-01-17)
-### 🎉 New features
 
@@ -18,5 +18,7 @@
 
-- setup.py: increase cubicweb max version to 3.38.x
+### 🎉 New feature
+
+setup.py: increase cubicweb max version to 3.38.x
 
 ### 🤖 Continuous integration
 
@@ -20,6 +22,6 @@
 
 ### 🤖 Continuous integration
 
-- gitlab-ci: use templates from a common repository
+gitlab-ci: use templates from a common repository
 
 ## Version 3.3.0 (2022-09-28)
@@ -24,6 +26,8 @@
 
 ## Version 3.3.0 (2022-09-28)
-### 🎉 New features
-- storages: Add bucket versioning support
+
+### 🎉 New feature
+
+storages: Add bucket versioning support
 
 ## Version 3.2.0 (2022-04-08)
@@ -28,4 +32,3 @@
 
 ## Version 3.2.0 (2022-04-08)
-### 🎉 New features
 
@@ -31,4 +34,6 @@
 
-- setup.py: increase cubicweb max version to 3.37.x
+### 🎉 Upgrade
+
+setup.py: increase cubicweb max version to 3.37.x
 
 ## Version 3.1.0 (2022-04-05)
@@ -33,9 +38,10 @@
 
 ## Version 3.1.0 (2022-04-05)
-### 🎉 New features
+
+### 🎉 New feature
 
 - cube-doctor: add add-set-cubicweb-max-version
 - setup.py: increase cubicweb max version to 3.35.x
 
 ### 📝 Documentation
 
@@ -36,10 +42,10 @@
 
 - cube-doctor: add add-set-cubicweb-max-version
 - setup.py: increase cubicweb max version to 3.35.x
 
 ### 📝 Documentation
 
-- licence: update licence dates
+licence: update licence dates
 
 ### 🤖 Continuous integration
 
@@ -43,8 +49,8 @@
 
 ### 🤖 Continuous integration
 
-- gitlab-ci: use templates from a common repository
+gitlab-ci: use templates from a common repository
 
 ### 🤷 Various changes
 
 - Bump version to 3.0.0
@@ -47,5 +53,5 @@
 
 ### 🤷 Various changes
 
 - Bump version to 3.0.0
-- storages: Fix log when key download fails
\ No newline at end of file
+- storages: Fix log when key download fails