Make the matcher and wrapper Ids in PatSyn into LocalIds, not GlobalIds
This was a serious bug, exposed by Trac #9175. The matcher and wrapper must be LocalIds, like record selectors and dictionary functions, for the reasons now documented in Note [Exported LocalIds] in Id.lhs In fixing this I found - PatSyn should have an Id inside it (apart from the wrapper and matcher) It should be a Name. Hence psId --> psName, with knock-on consequences - Tidying of PatSyns in TidyPgm was wrong - The keep-alive set in Desugar.deSugar (now) doesn't need pattern synonyms in it I also cleaned up the interface to PatSyn a little, so there's a tiny knock-on effect in Haddock; hence the haddock submodule update. It's very hard to make a test for this bug, so I haven't.