improve error message for #4214

[jangorecki]

improve error message for #4214

V = list(71L, c(71L, 132L), c(71L, 132L, 155L), 97L, 155L)
forder(V)
#Error in forderv(data, seq_along(data), sort = TRUE, retGrp = FALSE, order = if (decreasing) -asc else asc,  : 
#  Column 2 is length 2 which differs from length of column 1 (1), are you attempting to order by a list column?

[codecov]

Codecov Report

Merging #4343 into master will not change coverage by %.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #4343   +/-   ##
=======================================
  Coverage   99.61%   99.61%           
=======================================
  Files          72       72           
  Lines       13916    13916           
=======================================
  Hits        13862    13862           
  Misses         54       54           

Impacted Files	Coverage Δ
src/forder.c	100.00% <100.00%> (ø)

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[MichaelChirico]

LGTM 👍