Add documentation for new rule.
Add documentation for new rule.

wimh/coreutils,silvio/rust-coreutils,mauricio/coreutils,dennis/coreutils,bundai223/coreutils,Gianbaoluo/coreutils,uutils/coreutils,keunwoo/coreutils,beni55/coreutils,kevgeniy/coreutils,Arcterus/coreutils,beni55/coreutils,kball/coreutils,sshling/coreutils,dennis/coreutils,hexsel/coreutils,efuquen/coreutils,dbrgn/coreutils,Heather/coreutils,efuquen/coreutils,retep998/coreutils,kball/coreutils,kevgeniy/coreutils,Heather/coreutils,jbcrail/coreutils,filmor/coreutils,Shtong/coreutils,uutils/coreutils,steveklabnik/coreutils,ebfe/coreutils,jbcrail/coreutils,samfoo/coreutils,kwantam/coreutils,uutils/coreutils,dbrgn/coreutils,tempbottle/coreutils,Shir0kamii/coreutils,filmor/coreutils,mauricio/coreutils,wimh/coreutils,Shir0kamii/coreutils,Arcterus/coreutils,ebfe/coreutils,Gianbaoluo/coreutils,kwantam/coreutils,silvio/rust-coreutils,sshling/coreutils,samfoo/coreutils,keunwoo/coreutils,tempbottle/coreutils,retep998/coreutils,dbrgn/coreutils,bundai223/coreutils,steveklabnik/coreutils,Shtong/coreutils,hexsel/coreutils