Finish migrating user state over to MobX.

src/components/common/user/UserCheckbox.tsx

@@ -1,8 +1,9 @@
-import { User } from "revolt.js";
+import { User } from "../../../mobx";
 
 import Checkbox, { CheckboxProps } from "../../ui/Checkbox";
 
 import UserIcon from "./UserIcon";
+import { Username } from "./UserShort";
 
 type UserProps = Omit<CheckboxProps, "children"> & { user: User };
 
@@ -10,7 +11,7 @@ export default function UserCheckbox({ user, ...props }: UserProps) {
     return (
         <Checkbox {...props}>
             <UserIcon target={user} size={32} />
-            {user.username}
+            <Username user={user} />
         </Checkbox>
     );
 }