ci: improve changelog release notes extraction

Author: DecimalTurn

.github/workflows/prepare-release.yml

@@ -96,10 +96,10 @@ jobs:
         run: |
           version="${{ steps.next_version.outputs.version }}"
           # Extract lines between the version header and the next ## header
-          # Trim surrounding blank lines and normalize changelog issue refs from ([#123]) to (#123).
+          # Trim surrounding blank lines and normalize changelog issue refs (e.g. ([#123]), ([#123] & [#456]), ([#123] and [#456]), ([#123], [#456] and [#789])) by stripping square brackets.
           awk "/^## \\[$version\\]/{found=1; next} found && /^## /{exit} found{print}" CHANGELOG.md \
             | sed '/./,$!d' | sed -e :a -e '/^\s*$/{$d;N;ba}' \
-            | sed 's/(\[#\([0-9]\+\)\])/(#\1)/g' > release-notes.md
+            | sed 's/\[#\([0-9]\+\)\]/#\1/g' > release-notes.md
           if [[ ! -s release-notes.md ]]; then
             echo "(No changelog entries found for $version)" > release-notes.md
           fi