fix: commit type 항목 사이에만 쉼표가 들어가도록 수정 (#382)

Author: davidpro08

backend/src/markdown/builders/git-convention.builder.ts

@@ -77,10 +77,7 @@ export class GitConventionBuilder implements ISectionBuilder {
         lines.push('<summary>허용된 커밋 타입(Commit Types) 보기</summary>');
         lines.push('<div markdown=”1”>');
         lines.push('');
-        let commits = '';
-        commitTypes.forEach((type) => {
-          commits += `\`${type}\`, `;
-        });
+        const commits = commitTypes.map((type) => `\`${type}\``).join(', ');
         lines.push(commits);
         lines.push('');
         lines.push('</div>');