Enable @typescript-eslint/explicit-function-return-type in /src (#9788)

* Enable `@typescript-eslint/explicit-member-accessibility` on /src

* Prettier

* Enable `@typescript-eslint/explicit-function-return-type` in /src

* Fix types

* tsc strict fixes

* Delint

* Fix test

* Fix bad merge

src/hooks/useSmoothAnimation.ts

@@ -20,7 +20,7 @@ import { useCallback, useEffect, useRef, useState } from "react";
 import SettingsStore from "../settings/SettingsStore";
 import { useAnimation } from "./useAnimation";
 
-const debuglog = (...args: any[]) => {
+const debuglog = (...args: any[]): void => {
     if (SettingsStore.getValue("debug_animation")) {
         logger.log.call(console, "Animation debuglog:", ...args);
     }