Add a newline before the error message Markdown.

src/main/java/edu/hm/hafner/grading/AutoGradingRunner.java

@@ -215,7 +215,7 @@ protected String createErrorMessageMarkdown(final FilteredLog log) {
         if (log.hasErrors()) {
             var errors = new StringBuilder(ERROR_CAPACITY);
 
-            errors.append("## :construction: Error Messages\n```\n");
+            errors.append("\n## :construction: Error Messages\n```\n");
             var messages = new StringJoiner("\n");
             log.getErrorMessages().forEach(messages::add);
             errors.append(messages);

src/test/java/edu/hm/hafner/grading/AutoGradingRunnerITest.java

@@ -299,6 +299,17 @@ void shouldShowErrors() {
                         "Autograding score - 200 of 500"});
     }
 
+    @Test
+    void shouldShowNewlineBeforeErrorMessage() {
+        var runner = new AutoGradingRunner();
+        var log = new FilteredLog("Errors");
+        log.logError("This is an error");
+        assertThat(runner.createErrorMessageMarkdown(log))
+                .startsWith("\n")
+                .contains("## :construction: Error Messages")
+                .contains("This is an error");
+    }
+
     @Test
     void shouldReadDefaultConfigurationIfEnvironmentIsNotSet() {
         var runner = new AutoGradingRunner();