I reorged labels on Cabal's GitHub

[Edward Z. Yang]

Excerpts from Oleg Grenrus's message of 2016-07-12 04:03:43 -0700:
> Looks good indeed!
> 
> I have few questions:
> - what is purpose of `paging:*` labels, to help people see issues they are interested in? How it’s different from assignees (which can be multiple)?

Beyond what Mikhail stated:

    - Multiple people can be paged, only one assigned
    - I can put more metadata in the tag name than assignable
      (to help people decide who to page)

But it's an experiment. If it's not useful we can delete the tags.

> - why “bug” has “ezyang planning to delete this tag”. I’d prefer to have “type: bug” and other “type:*” labels as:  “type: discuss”, “type: enhancement”, “type: question”, and maybe more as e.g. stack has https://github.com/commercialhaskell/stack/labels <https://github.com/commercialhaskell/stack/labels>

OK, the tag served it's purpose! I planned to delete it because there
are lots of bugs in the issues tracker and no one has been methodically
tagging them bug or not, so it seemed that the tag was just not that
helpful.  Just look at Stack's issues list: https://github.com/commercialhaskell/stack/issues
who is tagging things as bugs!

discuss/enhancement/question are useful and I support tags for them.
Presently we have "priority: enhancement" but we can rename that as
needed.

> - how priority labels interact with milestones?

Agreed with Mikhail; priority within milestone.

> - Should we add “pr welcome” or “awaiting pr” for issues which are discussed, but nobody have interest or time implementing right away (will help new contributors especially when combined with `meta: easy`)

Sure! I wonder, however; for tickets that are tagged this way, I feel
the onus is on us to write a clear spec at the top of the bug for what
is desired (even better: link to a commit with a test!)  Will help
contributors a lot.

Edward