fix deprecation warning

Author: dmonad

test/test.cjs

@@ -24,8 +24,6 @@ global.innerHeight = 0
 // @ts-ignore
 document.getSelection = () => ({ rangeCount: 0, removeAllRanges: () => {}, addRange: () => {} })
 // @ts-ignore
-document.execCommand = () => {}
-// @ts-ignore
 document.createRange = () => ({
   setStart: () => {},
   setEnd: () => {}