--edit option to overwrite file

[bastien-k]

When doing something like:
cat foo.py | sgpt --code "add docstring to this code" > foo.py
Linux first empties foo.py before sgpt can read it, so it eventually reads an empty file and writes garbage.
This is due to how Linux orders the actions between | and > and it was confusing to me, at first.

This works:
cat foo.py | sgpt --code "add docstring to this code" > foo_new.py
Which you can follow by:
mv foo_new.py foo.py

But what about introducing this:
sgpt --edit foo.py --code "add docstring to this code"

It could also be used for non-code tasks, like:
sgpt --edit essay.txt "find and correct grammar errors"

[bastien-k]

As an alternative fix, I made this shell function:

function sgpt-edit
    set file $argv[1]
    set string $argv[2]
    set temp_file (mktemp -p /tmp)

    cat $file | sgpt $string > $temp_file && mv $temp_file $file
end

Used like this:
sgpt-edit test.txt "translate that text in French"