Deprecate useDebounce and useThrottle in favor of the Callback hooks #537

useDebounce and useThrottle return a wrapped function, but the names do not say so, and other hook libraries use the same names for hooks that return a debounced or throttled value. useDebouncedCallback and useThrottledCallback cannot replace them yet, because they forward a single value and have no cancel.

• Let useDebouncedCallback and useThrottledCallback wrap a function with any arguments and return it with cancel.
• Mark useDebounce and useThrottle as deprecated and point their docs to the Callback hooks.
• useImpressionRef relies on the Callback hook skipping a repeated call with the same value. Keep that behavior, either in the Callback hook or in useImpressionRef.

Update types, docs, and tests.

Waits for #530 and #534.