eslint-plugin-react-hooks: lint rule to enforce that `useMemo` returns a value

Nothing prevents developers from calling `useMemo` without a `return`: ```ts import { useMemo } from "react"; useMemo(() => { console.log("Yippee!"); }, []); ``` [[TypeScript playground showing no errors](https://www.typescriptlang.org/play?#code/JYWwDg9gTgLgBAbzgVwM4FMCy6QTgXzgDMoIQ4AiKdAQwGMYKBuAWACh20scIAKXgJRwAvAD5E7OFLh0IAO1QQANugB0SiAHNeFAJrAwYdOgCEFAazb4ANHADaAXQtA)] Calling `useMemo` without a returned value is somewhat equivalent to calling `useEffect` without a returned value. Judging by the few times I've seen it happen, it's likely a case of a developer either confusing the two hooks or forgetting to `return` the memoized value. Suggestion: can we add a lint rule to flag `useMemo` calls that don't definitely return a value? It could have a _suggestion_ fixer to switch to `useEffect`.