fix: ensure newline before </details> when truncating

lib/platform/utils/__snapshots__/pr-body.spec.ts.snap

@@ -35,7 +35,9 @@ exports[`platform/utils/pr-body .smartTruncate truncates to 1000 1`] = `
 
 ##### Features
 
--   **docker:** AWS ECR authentication support ([#&#8203;4497](https:</details>
+-   **docker:** AWS ECR authentication support ([#&#8203;4497](https://
+
+</details>
 
 ---
 

lib/platform/utils/pr-body.ts

@@ -6,7 +6,7 @@ export function smartTruncate(input: string, len: number): string {
   }
   const releaseNotesMatch = re.exec(input);
   if (releaseNotesMatch) {
-    const divider = `</details>\n\n---\n\n### Configuration`;
+    const divider = `\n\n</details>\n\n---\n\n### Configuration`;
     const [releaseNotes] = releaseNotesMatch;
     const nonReleaseNotesLength =
       input.length - releaseNotes.length - divider.length;