display no error if there is none when committing with a clean working directory

[inktrap]

Like the title says. The plugin merges stdout and stderr in helper/git.ts commit which leads to messages and thus displays messages from stout as errors, even if there are none. Background info: I press CTRL+s too often, can't help it, and it leads to these annoying error messages that I have to click to remove. If you decide to display this case of stdout as a notice one day, please add an option to silence that, I would appreciate it.