fix(guardKey): change return from boolean to value is Key

Author: sciborrudnicki

packages/type/src/guard/type/guard-key.type.ts

@@ -1,3 +1,3 @@
 import { Key } from '../../type/key.type';
 import { ResultCallback } from '../../type/result-callback.type';
-export type GuardKey = (value: Key, callback?: ResultCallback) => boolean;
+export type GuardKey = (value: Key, callback?: ResultCallback) => value is Key;