Function last_path_segment 

pub const fn last_path_segment(path: &str) -> &str

Last ::-separated segment of a module path. 模块路径中最后一段 :: 分隔的分量。

Public because the declaration macros call it from the host crate to derive a face’s registry name from module_path!(). 公开是因为注册面宏在宿主 crate 里调用它，从 module_path!() 推导注册机名。