hi.  i occasionally need to look up how to get header lines on tables
resulting from an evaluation of an R source block.  the answer is
=:colnames yes=.  here's a patch that minimally documents that.

cheers, Greg

ps -- i have some vague memory i'm supposed to hack in a "woof" header.
but, it's not mentioned on https://orgmode.org/contribute.html so i've
lazily not.