[x-core-lib] (英语). 缺少惊慌症医生

`Style:::new ()' 声明,但Rust文件缺少惊慌症。 (https://docs.rs/time/0.3.28/time/struct.Date.html#method.prev occurrence) 最好添加恐慌状态.

https://GitHub.com/xi-editor/xi-editor/blob/a2dea3059312795c77caadc639df49bf8a7008eb/ZRust/core-lib/src/styles.rs#L80-L102