chore(NODE-5543): fix duplicate PR highlights (#610)

Author: nbbeeken

.github/scripts/highlights.mjs

@@ -70,7 +70,10 @@ async function pullRequestHighlights(prs) {
   if (!highlights.length) return '';
 
   highlights.unshift('## Release Notes\n\n');
-  return highlights.join('\n\n');
+
+  const highlight = highlights.join('\n\n');
+  console.log(`Total highlight is ${highlight.length} characters long`);
+  return highlight;
 }
 
 console.log('List of PRs to collect highlights from:', prs);

.github/scripts/pr_list.mjs

@@ -13,10 +13,14 @@ const historyFilePath = path.join(__dirname, '..', '..', 'HISTORY.md');
  */
 function parsePRList(history) {
   const prRegexp = /js-bson\/issues\/(?<prNum>\d+)\)/iu;
-  return history
-    .split('\n')
-    .map(line => prRegexp.exec(line)?.groups?.prNum ?? '')
-    .filter(prNum => prNum !== '');
+  return Array.from(
+    new Set(
+      history
+        .split('\n')
+        .map(line => prRegexp.exec(line)?.groups?.prNum ?? '')
+        .filter(prNum => prNum !== '')
+    )
+  );
 }
 
 const historyContents = await fs.readFile(historyFilePath, { encoding: 'utf8' });