Add promise type to fetches

src/utils/fetches/instanceFetch.ts

@@ -3,7 +3,7 @@ import client from '@api/client'
 export const instanceFetch = async (
   key: string,
   { instanceDomain }: { instanceDomain: string }
-) => {
+): Promise<Mastodon.Instance> => {
   const res = await client({
     method: 'get',
     instance: 'remote',