False positive of the SH.FLOW.CheckReturn rule

### Expected behavior
A blank line between a command and the return check should not raise a violation on the command line

### Actual behavior
A blank line causes a correct check to raise a violation

### Steps to reproduce behavior
cd $HOME

if [ $? -eq 0 ]; then
echo "echec du cd"
exit 1
else
ls
if [ $? -eq 0 ]; then
echo "echec du ls"
exit 1
fi
fi

### Detection version
3.1.0-dev