Add preventScroll check

src/utilities/support.ts

@@ -0,0 +1,15 @@
+//
+// Determines if the browser supports focus({ preventScroll })
+//
+export function isPreventScrollSupported() {
+  let supported = false;
+
+  document.createElement('div').focus({
+    get preventScroll() {
+      supported = true;
+      return false;
+    }
+  });
+
+  return supported;
+}