missing definition of 'list'

docker run --help etc. mentions several times list as an option argument but does not define, what a list actually is. E.g.:

      --dns list                       Set custom DNS servers
      --dns-option list                Set DNS options
      --dns-search list                Set custom DNS search domains

I've tried e.g. --dns '1.2.3.4,5.6.7.8' but this does not work and results into

invalid argument "1.2.3.4,5.6.7.8" for "--dns" flag: 1.2.3.4,5.6.7.8 is not an ip address
See 'docker run --help'.

Also the man page is wrong: It shows e.g.

--dns=[]  Set custom DNS servers

[] denotes optional arguments in man pages. Since it does not contain any argument, it is actually the same as --dns (does not allow any argument).

So it should be documented/defined, what a list is/what docker actually expects as argument.

Start by running docker run --help and reviewing the generated man-page output for --dns, --dns-option, and --dns-search. Trace where these option descriptions are defined and how their arguments are parsed. Done means the help text and man page consistently define the expected list syntax and no longer show misleading empty brackets.