seq no longer mishandles cases like "seq 0 0.000001 0.000003",

seq no longer mishandles cases like "seq 0 0.000001 0.000003",
where it would not print the desired last number.
* doc/coreutils.texi (seq invocation): Remove advice about workaround
for seq off-by-one problem, since the bug is fixed now.  Replace
it with more-generic advice about rounding errors.
* src/seq.c (long_double_format, print_numbers):
New arg NUMERIC_FORMAT.  All uses changed.