fix: DispatchWorker missing a 2-element stop clause in handle_info

[mdlkxzmcp]

As pointed out in the #203 (comment), the {:stop, reason} clause is missing, which leads to CaseClauseErrors instead of proper error handling.

I also moved the handle_info callback below handle_push as it mentions "all other messages", which logically should be a follow-up to what handle_push` has in its doc.

As a side note, I couldn't find a case in which {:stop, reason, new_state} for handle_info is invoked, but I didn't want to accidentally break anything, so I left it as it was :)

[hpopp]

Thanks for this!