perf(useRuleFormItem): more accurate return type (#1290)

src/hooks/component/useFormItem.ts

-import type { UnwrapRef, Ref } from 'vue';
+import type { UnwrapRef, Ref, WritableComputedRef, DeepReadonly } from 'vue';
 import {
   reactive,
   readonly,
@@ -12,6 +12,13 @@ import {
 
 import { isEqual } from 'lodash-es';
 
+export function useRuleFormItem<T extends Recordable, K extends keyof T, V = UnwrapRef<T[K]>>(
+  props: T,
+  key?: K,
+  changeEvent?,
+  emitData?: Ref<any[]>,
+): [WritableComputedRef<V>, (val: V) => void, DeepReadonly<V>];
+
 export function useRuleFormItem<T extends Recordable>(
   props: T,
   key: keyof T = 'value',