refactor: 优化词法分析错误输出格式

-将错误信息前的缩进从两个空格改为一个制表符，提高可读性

src/main/java/org/jcnc/snow/compiler/lexer/core/LexerEngine.java

@@ -69,7 +69,7 @@ public class LexerEngine {
             return;
         }
         System.err.println("\n词法分析发现 " + errors.size() + " 个错误: ");
-        errors.forEach(e -> System.err.println("  " + e));
+        errors.forEach(e -> System.err.println("\t" + e));
     }
 
     public List<Token> getAllTokens() { return List.copyOf(tokens); }