[GHC] #15195: Merge -XPolyKinds with -XTypeInType

[GHC]

#15195: Merge -XPolyKinds with -XTypeInType
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        Reporter:  goldfire          |                Owner:  int-index
            Type:  bug               |               Status:  merge
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.2.2
      Resolution:  fixed             |             Keywords:  GHCProposal
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D4748
       Wiki Page:                    |
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Comment (by bgamari):

 Well, to be clear, the `ghc-8.6` branch does exist but it's still tracking
 `master`. By the end of the day I suspect it will begin diverging.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15195#comment:9>
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