Enable to use external editor to make request body

[Shinsuke Hamasho]

Thanks for this awesome software.
I can now make HTTP request very easily.

But sometimes, I have to use an editor and other software to make requests with complicated body.

I use a simple script like this;

#!/usr/bin/zsh
# command name: httpj

TMPFILE=$(mktemp --suffix=.json)
vim $TMPFILE
http "$@" < $TMPFILE
rm $TMPFILE

It would be nice if http-prompt launches an external editor with a keyboard short cut, and stores the saved file as the next request's body.