Kernel: Make tty overload correct has_data() function

This allows snake game to work again :)

kernel/include/kernel/Terminal/TTY.h

@@ -40,7 +40,7 @@ namespace Kernel
 		void putchar(uint8_t ch);
 		virtual void putchar_impl(uint8_t ch) = 0;
 
-		bool has_data() const;
+		virtual bool has_data_impl() const override;
 
 	protected:
 		TTY(mode_t mode, uid_t uid, gid_t gid)

kernel/kernel/Terminal/TTY.cpp

@@ -328,7 +328,7 @@ namespace Kernel
 		return count;
 	}
 
-	bool TTY::has_data() const
+	bool TTY::has_data_impl() const
 	{
 		LockGuard _(m_lock);
 		return m_output.flush;