I'd like to propose an addition to info-look.el for sh-mode command
and variable lookups.

For commands I think the invocation is the most pertinent information
when writing a shell script.  This is the natural form in the bash and
coreutils manuals, I fudged the sed and awk entries to go to their
command line sections too.

I guess almost every program is a candidate for sh-mode lookup, but
there's no call to go overboard, the theory would just be to cover the
common things.

	* info-look.el (sh-mode): Add doc-specs for commands and variables.