fix: EqualFunc not deterministic

The `ExampleEqualFunc_badEqualFunc` was non-deterministic, because the hashes used in the `CustomTable` could (by chance) map "Rob"
 and "Robert" to the same slot. Updated the test to use a deterministic hash.

compare_example_test.go

@@ -13,11 +13,22 @@ import (
 func ExampleEqualFunc_badEqualFunc() {
 	type User struct{ ID, Name string }
 
+	makeHash := func(seed uint64) cuckoo.Hash[User] {
+		return func(u User) uint64 {
+			digest := seed
+
+			for _, c := range u.ID + u.Name {
+				digest ^= uint64(c)
+			}
+
+			return digest
+		}
+	}
+
 	// Two users with the same ID are equal.
 	isEqual := func(a, b User) bool { return a.ID == b.ID }
 
-	hashA, hashB := cuckoo.NewDefaultHash[User](), cuckoo.NewDefaultHash[User]()
+	userbase := cuckoo.NewCustomTable[User, bool](makeHash(1), makeHash(2), isEqual)
-	userbase := cuckoo.NewCustomTable[User, bool](hashA, hashB, isEqual)
 
 	(userbase.Put(User{"1", "Robert Doe"}, true))