`run` ignores "content"

[bovine3dom]

"content" is supposed to be stdin:

https://github.com/tridactyl/tridactyl/blob/e3f08611f743f42ad3e7bc264f07a570ea580667/native/native_main.py#L424

Suggested fix by @chaoyi https://gist.github.com/chaoyi/37a399f11335da12183fdc51f05df329