Support anonymous named and anonymous shared shared mappings in /proc/PID/maps #318
Description
Linux allows naming anonymous mappings, both shared and non-shared. Named anonymous mappings appear as [anon:<name>] entries while anonymous shared named mappings appear as [anon_shmem:<name>] lines (see the kernel documentation). Since in both cases the name is optional I propose to extend the MmapPath::Anonymous with an optional string name, so MmapPath::Anonymous(Option<String>) and introduced a similar entry for anonymous shared mappings (say MmapPath::AnonymousShared(Option<String>).