Error in "fit" documentation?

[Ethan A M. <sf...@us...>]

Current documentation for "fit" says

  Note that if you don't pecify a `using` option at all, no z standard
  deviations are read from the datafile even if it does have a third 
  column, so you'll always get unit weights.

But from looking at the code I think this is not true.  If there is
no using spec then the number of independent variables is always two
less than the number of columns in the input file, and the final 
input column is indeed interpreted as a standard deviation on z.

The comment in the fit.c source code is also wrong, as it claims
that the standard deviation is used only if there is an explicit
using spec.

Have I misread this?

	Ethan