interp: here-doc backslash is not preserved

[mochja]

When a backslash is present inside here-doc it is not preserved in the output(input). See the difference with bash below:

gosh
$ cat << EOF
> test \" test
> EOF
test " test

bash
bash-3.2$ cat << EOF
> test \" test
> EOF
test \" test

Relates to:

• The 'cat << EOF' produces wrong output when using escaped quotes go-task/task#1538

[mvdan]

Thanks, this looks like a bug in the parser. I didn't know that heredocs treat backslashes unlike any other part of the language.