ln: remove note about hard links for directories
ln: remove note about hard links for directories

Hard links are generally not allowed for directories.
UncommonPleb/tldr,zoisom/tldr,zoisom/tldr,cptdeka10/tldr,kuanyui/tldr,Phizho/tldr,WALL-E/tldr,AgamAgarwal/tldr,UncommonPleb/tldr,mshmoustafa/tldr,rubenvereecken/tldr,ArturSkowronski/tldr,katekyan/tldr,felixonmars/tldr,igorshubovych/tldr,AgamAgarwal/tldr,zoisom/tldr,felixonmars/tldr,felixonmars/tldr,Phizho/tldr,deekim/tldr,rubenvereecken/tldr,deekim/tldr,mshmoustafa/tldr,slash3b/tldr,kuanyui/tldr,ArturSkowronski/tldr,WALL-E/tldr,UncommonPleb/tldr,katekyan/tldr,igorshubovych/tldr,slash3b/tldr,cptdeka10/tldr,Phizho/tldr,slash3b/tldr,deekim/tldr,cptdeka10/tldr,katekyan/tldr