[Bug-readline] rl_insert_text() insert only one line

[Cade Foster]

Readline version number: 6.3.

Code example from official site:
https://cnswww.cns.cwru.edu/php/chet/readline/rl.c

Package
http://archive.ubuntu.com/ubuntu/pool/main/r/readline6/libreadline6_6.3-4ubuntu2_amd64.deb
and
upstream snapshot
http://git.savannah.gnu.org/cgit/readline.git/snapshot/readline-master.tar.gz
(downloaded 13 May 2016)

Compilation commands:

tar --extract --file readline-master.tar.gz --gzip
cd readline-master/
./configure
make
cd ..

gcc -c rl.c -o rl.o
gcc rl.o ./readline-master/libreadline.a -o rl

Usage of rl:
rl [-p prompt] [-u unit] [-d default] [-n nchars]

Assume you terminal width is 10 columns.
When command

./rl -p '> ' -d '0123456789'

will print single line

89|01234567

but expected result is printing two lines

> 01234567
89|

where vertical bar "|" is cursor position.

Problem: function rl_insert_text()
can't insert long text on multiple lines.