fix: lint error for unused property

src/handlebars/helpers/math.ts

@@ -13,7 +13,7 @@ import Handlebars from 'handlebars'
  */
 export function addHelper(): void {
   Handlebars.registerHelper('add', function (...args) {
-    const options = args.pop()
+    args.pop()
     return args.reduce((sum: number, value: number) => sum + (value || 0), 0) as number
   })
 }