chore: optimize string search with Aho–Corasick algorithm (#1476)

* chore: optimize string search with Aho–Corasick algorithm

* chore: optimize keywords replacer

* fix: replacer bugs

* chore: reorder members

core/stringx/node_test.go

@@ -0,0 +1,25 @@
+package stringx
+
+import "testing"
+
+func BenchmarkNodeFind(b *testing.B) {
+	b.ReportAllocs()
+
+	keywords := []string{
+		"A",
+		"AV",
+		"AV演员",
+		"无名氏",
+		"AV演员色情",
+		"日本AV女优",
+	}
+	trie := new(node)
+	for _, keyword := range keywords {
+		trie.add(keyword)
+	}
+	trie.build()
+
+	for i := 0; i < b.N; i++ {
+		trie.find([]rune("日本AV演员兼电视、电影演员。无名氏AV女优是xx出道, 日本AV女优们最精彩的表演是AV演员色情表演"))
+	}
+}