completely parse `:augroup` and `:autocmd`

[tjdevries]

There are some options that we are not yet parsing for both :augroup and :autocmd that we need to do. Once we do that, we should correspondingly pass those options into the gen and generate correctly.

For example, I think ++once is not getting parsed right now. So then you could add an integration test that parses those and then executes the command checks the length of the current autocmds associated with an event (and make sure it's one less than it was before, for example)