修复JSONStrFormatter:format函数对于转义符号处理逻辑错误问题

hutool-json/src/test/java/cn/hutool/json/IssueI84V6ITest.java

@@ -0,0 +1,18 @@
+package cn.hutool.json;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class IssueI84V6ITest {
+	@Test
+	public void formatTest() {
+		final String a1 = "{'x':'\\n','y':','}";
+		final String formatJsonStr = JSONUtil.formatJsonStr(a1);
+//		Console.log(formatJsonStr);
+		Assert.assertEquals(
+			"{\n" +
+				"    'x': '\\n',\n" +
+				"    'y': ','\n" +
+				"}", formatJsonStr);
+	}
+}