close #31481 currently `$$A + B$$ test` will ignore text after $$ block test text ![圖片](https://github.com/go-gitea/gitea/assets/30816317/39b2974b-c0b6-48a0-87d0-5f4a13615eed) before fix ![圖片](https://github.com/go-gitea/gitea/assets/30816317/15469e4c-474d-4128-b46f-d6cadaafbd68) after fix ![圖片](https://github.com/go-gitea/gitea/assets/30816317/c1025eef-177f-4ade-988f-510e7039f3f9) github display ![圖片](https://github.com/go-gitea/gitea/assets/30816317/97cd1e10-ac94-4899-86d8-8e359ef1d694)