Update mod.ts

Author: Mqxx

src/format/mod.ts

@@ -1,7 +1,9 @@
 import replacePlaceholder from "./replace_placeholder.ts";
 import truncate from "./truncate.ts";
+import joinAnd from "./join_and.ts"
 
 export const format = { 
   replacePlaceholder,
   truncate,
+  joinAnd
 }