rebase: fix code comment to refer to right issue (4504, not 4505)
The comment was introduced in 8a544fb645bb (rebase: ensure rebase
revision remains visible (issue4504), 2015-01-27), which mentions the
right issue in the description.
#!/bin/sh
HGENCODING=UTF-8
export HGENCODING
echo ".. -*- coding: utf-8 -*-" > gendoc.txt
echo "" >> gendoc.txt
LANGUAGE=$1 python "$TESTDIR/../doc/gendoc.py" >> gendoc.txt 2> /dev/null || exit
echo "checking for parse errors"
python "$TESTDIR/../doc/docchecker" gendoc.txt
python "$TESTDIR/../doc/runrst" html gendoc.txt /dev/null