format ~F with scale factor wrong

[Douglas Katzman]

* (format t "~,3,-6f" 43355281)
43.35528

The "k" parameter does not give license to alter the "d" parameter.

"The full form is ~w,d,k,overflowchar,padcharF. The parameter w is the width of the field to be printed; d is the number of digits to print after the decimal point; k is a scale factor that defaults to zero."