Function hooks_commit_msg

pub fn hooks_commit_msg(
    repo_path: &RepoPath,
    msg: &mut String,
) -> Result<HookResult>

this hook is documented here https://git-scm.com/docs/githooks#_commit_msg we use the same convention as other git clients to create a temp file containing the commit message at <.git|hooksPath>/COMMIT_EDITMSG and pass it’s relative path as the only parameter to the hook script.