优化游戏下载页版本分类功能 (#4141)

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

HMCLCore/src/main/java/org/jackhuang/hmcl/util/versioning/GameVersionNumber.java

@@ -98,6 +98,10 @@ public abstract class GameVersionNumber implements Comparable<GameVersionNumber>
         this.value = value;
     }
 
+    public boolean isSpecial() {
+        return this instanceof Special;
+    }
+
     enum Type {
         PRE_CLASSIC, CLASSIC, INFDEV, ALPHA, BETA, NEW
     }