fix(changelog): fix assoc array syntax for zsh 5.4.2 and older (#9495)

Also fixed a call to a defunct display:type-header function in displaying
breaking changes.

tools/changelog.sh

@@ -8,16 +8,16 @@
 #* and the display string of such type
 local -A TYPES
 TYPES=(
-  [build]="Build system"
-  [chore]="Chore"
-  [ci]="CI"
-  [docs]="Documentation"
-  [feat]="Features"
-  [fix]="Bug fixes"
-  [perf]="Performance"
-  [refactor]="Refactor"
-  [style]="Style"
-  [test]="Testing"
+  build     "Build system"
+  chore     "Chore"
+  ci        "CI"
+  docs      "Documentation"
+  feat      "Features"
+  fix       "Bug fixes"
+  perf      "Performance"
+  refactor  "Refactor"
+  style     "Style"
+  test      "Testing"
 )
 
 #* Types that will be displayed in their own section,
@@ -274,8 +274,8 @@ function display-release {
     (( $#breaking != 0 )) || return 0
 
     case "$output" in
-    raw) display:type-header "BREAKING CHANGES" ;;
-    text|md) display:type-header "⚠ BREAKING CHANGES" ;;
+    raw) fmt:header "BREAKING CHANGES" 3 ;;
+    text|md) fmt:header "⚠ BREAKING CHANGES" 3 ;;
     esac
 
     local hash subject