Handle the recurrence formats properly

[MetRonnie]

Been a while since I've looked at this repo, but there's a comment here which ought to be resolved at some point (not sure if it's valid or not) https://github.com/cylc/cylc-textmate-grammar/blob/e40ae6d2e643ce0d930767178daacb5ce08bd21a/src/cylc.tmLanguage.js#L273