fix(parser): correct newline escaping in test cases

Update test cases in `CodeUtilTest.kt` to use proper newline characters (`\n`) instead of escaped versions (`\\n`) for markdown and HTTP request content parsing.

core/src/test/kotlin/cc/unitmesh/devti/parser/CodeUtilTest.kt

@@ -55,14 +55,14 @@ class CodeUtilTest {
 
     @Test
     fun should_handle_pure_markdown_content() {
-        val content = "```markdown\\nGET /wp/v2/posts\\n```"
+        val content = "```markdown\nGET /wp/v2/posts\n```"
         val code = Code.parse(content)
         assertEquals(code.text, "GET /wp/v2/posts")
     }
 
     @Test
     fun should_handle_http_request() {
-        val content = "```http request\\nGET /wp/v2/posts\\n```"
+        val content = "```http request\nGET /wp/v2/posts\n```"
         val code = Code.parse(content)
         assertEquals(code.text, "GET /wp/v2/posts")
     }