lib/sh/util.sh: set_fd()/shadow_fd(): take the redirect expr as an arg instead of a kw_param because it's the only param

lib/sh/util.sh: set_fd()/shadow_fd(): take just a redirect expr containing the entire dest[<>]src expr, and parse the dest out from it

lib/sh/util.sh: set_fd()/shadow_fd(): updated usage and kw_params

lib/sh/util.sh: set_fd()/shadow_fd(): updated usage and kw_params

lib/sh/util.sh: set_fd()/shadow_fd(): take just a redirect source expr containing the <> and the fd, to allow the caller to specify these in the shell redirection syntax. this also allows using a file (such as /dev/null) as the redirect source.

lib/sh/util.sh: added cd() wrapper that logs itself and indents (indent is permanent within subshell cd was used in)

lib/sh/util.sh: added caller_indent alias

lib/sh/util.sh: log_err(): changed symbol to # instead of * so that it stands out better at the outmost indent level and doesn't blend in with the + that will be prefixing other messages

lib/sh/util.sh: log_info(): changed symbol to : so that it blends in better with the | lines (looking like a dotted segment of the line), but still stands out (because of the dots)

*{.sh,run}: don't use aliases unless it's actually necessary (e.g. to define a var in the calling function, or to alias-expand the next word)