feat: Add test for Unicode styled word counting

Author: HowieHz

src/test/java/top/howiehz/halo/plugin/extra/api/utils/PostWordCountUtilTest.java

@@ -77,7 +77,7 @@ void testCountPlainTextWordsNullAndEmpty() {
 
     @Test
     void safeCountAsciiWords() {
-        // 测试英文单词计数
+        // 测试英文单词/数字计数
         assertEquals(BigInteger.valueOf(3),
             PostWordCountUtil.countPlainTextWords("Hello world test"));
         assertEquals(BigInteger.valueOf(4),
@@ -86,6 +86,8 @@ void safeCountAsciiWords() {
         assertEquals(BigInteger.valueOf(2), PostWordCountUtil.countPlainTextWords("Hello world!"));
         assertEquals(BigInteger.valueOf(3), PostWordCountUtil.countPlainTextWords("Hello, Halo 2"));
         assertEquals(BigInteger.valueOf(2), PostWordCountUtil.countPlainTextWords("10.11"));
+        // 𝓗𝑒𝓵𝓵𝑜 𝓌𝑜𝓇𝓁𝒹
+        assertEquals(BigInteger.valueOf(2), PostWordCountUtil.countPlainTextWords("\uD835\uDCD7\uD835\uDC52\uD835\uDCF5\uD835\uDCF5\uD835\uDC5C \uD835\uDCCC\uD835\uDC5C\uD835\uDCC7\uD835\uDCC1\uD835\uDCB9"));
     }
 
     @Test