Drop support for extra commas in node patterns
Drop support for extra commas in node patterns

The node pattern compiler had an undocumented feature, in that it would
allow any number of commas within patterns, e.g.:

```
(send, nil,, :foo)
```

IMHO, this only leads to less concise patterns, with more punctuation
noise from non-functional characters. So I suggest dropping support.

The codebase currently doesn't contain any node patterns with commas,
but there is a small chance there are user generated custom cops using
this, which risk breaking.

mikegee/rubocop,sue445/rubocop,maxjacobson/rubocop,smakagon/rubocop,palkan/rubocop,b-t-g/rubocop,lumeet/rubocop,tdeo/rubocop,bquorning/rubocop,vergenzt/rubocop,urbanautomaton/rubocop,akihiro17/rubocop,alexcstark/rubocop,urbanautomaton/rubocop,scottmatthewman/rubocop,tejasbubane/rubocop,deivid-rodriguez/rubocop,pocke/rubocop,haziqhafizuddin/rubocop,palkan/rubocop,bbatsov/rubocop,jmks/rubocop,panthomakos/rubocop,alexcstark/rubocop,rrosenblum/rubocop,mikegee/rubocop,akihiro17/rubocop,tdeo/rubocop,palkan/rubocop,iGEL/rubocop,vergenzt/rubocop,petehamilton/rubocop,mikegee/rubocop,smakagon/rubocop,tdeo/rubocop,bquorning/rubocop,panthomakos/rubocop,deivid-rodriguez/rubocop,meganemura/rubocop,tejasbubane/rubocop,vergenzt/rubocop,iGEL/rubocop,lumeet/rubocop,maxjacobson/rubocop,jfelchner/rubocop,NobodysNightmare/rubocop,jmks/rubocop,sue445/rubocop,akihiro17/rubocop,rrosenblum/rubocop,pocke/rubocop,jfelchner/rubocop,jfelchner/rubocop,meganemura/rubocop,petehamilton/rubocop,maxjacobson/rubocop,deivid-rodriguez/rubocop,panthomakos/rubocop,rrosenblum/rubocop,sue445/rubocop,bbatsov/rubocop,bquorning/rubocop,tejasbubane/rubocop,meganemura/rubocop,b-t-g/rubocop,haziqhafizuddin/rubocop,scottmatthewman/rubocop,NobodysNightmare/rubocop,petehamilton/rubocop,jmks/rubocop