fix: omit empty release note sections

package.json

@@ -1,6 +1,6 @@
 {
   "name": "tallynote",
-  "version": "1.1.28",
+  "version": "1.1.29",
   "private": true,
   "type": "module",
   "packageManager": "pnpm@9.0.6",

scripts/publish-gitea-release.sh

@@ -109,11 +109,11 @@ generate_release_notes() {
     for item in "$@"; do printf -- '- %s\n' "$item"; done
     printf '\n'
   }
-  print_group '新增功能' "${features[@]-}"
-  print_group '问题修复' "${fixes[@]-}"
-  print_group '优化与重构' "${improvements[@]-}"
-  print_group '文档与测试' "${docs[@]-}"
-  print_group '其他变更' "${other[@]-}"
+  ((${#features[@]})) && print_group '新增功能' "${features[@]}"
+  ((${#fixes[@]})) && print_group '问题修复' "${fixes[@]}"
+  ((${#improvements[@]})) && print_group '优化与重构' "${improvements[@]}"
+  ((${#docs[@]})) && print_group '文档与测试' "${docs[@]}"
+  ((${#other[@]})) && print_group '其他变更' "${other[@]}"
   if (( ${#features[@]} + ${#fixes[@]} + ${#improvements[@]} + ${#docs[@]} + ${#other[@]} == 0 )); then
     printf '本版本包含内部维护更新。\n'
   fi