fix cspell and ts

cspell.json

@@ -109,6 +109,7 @@
     "novalidate",
     "npmdir",
     "Numberish",
+    "onscrollend",
     "outdir",
     "ParamagicDev",
     "peta",

src/internal/scrollend-polyfill.ts

@@ -69,3 +69,6 @@ if (!isSupported) {
     }
   });
 }
+
+// Without an import or export, TypeScript sees vars in this file as global
+export {};