[bug] puni-convolute in sh-mode

the following code (<|> is the point):

```sh
for f in `ls -1`; do
    if [ -z "$SKIP_JOB" ]; then
        <|>echo "do job with $f";
    fi
done
```

When issuing `puni-convolute` becomes:

```sh
if [ -z "$SKIP_JOB" ]; then
    for f in `ls -1`; do
        echo "do job with $f";
    
donefi
```

I.e. it almost works: `done` and `fi` are concatenated.