add return type

Author: xr0master

src/utils/isHeadless/isHeadless.ts

@@ -1,3 +1,3 @@
-export const isHeadless = (navigator: Navigator) => {
+export const isHeadless = (navigator: Navigator): boolean => {
   return navigator.webdriver || !navigator.languages || navigator.languages.length === 0;
 };