Make example keyset pagination header parsing consistent (#41890)

Co-authored-by: Sharra-writes <sharra-writes@github.com>

Author: PauwelsPieter

content/rest/using-the-rest-api/using-pagination-in-the-rest-api.md

@@ -127,7 +127,7 @@ const octokit = new Octokit({ {% ifversion ghes %}
 {% endif %}});
 
 async function getPaginatedData(url) {
-  const nextPattern = /(?<=<)([\S]*)(?=>; rel="Next")/i;
+  const nextPattern = /(?<=<)([\S]*)(?=>; rel="next")/i;
   let pagesRemaining = true;
   let data = [];